Time to Unleash Carson

The following is a post by @sunset_shazz.

The National Football League has, over time, become a passing league. The best, most analytically sophisticated teams build around the passing game. In 2018, the final four teams in the NFC and AFC Championship games enjoyed the top 4 passing offenses, in terms of efficiency. In 2019, run-first teams are typically built by dinosaurs who can barely dress themselves.

The Philadelphia Eagles have made forward-thinking analytics a centerpiece of their strategy, and their fearless head coach is a protégé of one of the game’s great passing innovators; surely they are a pass-friendly offense?

How often do teams pass when it's up to them?

--Chiefs, Bills, Packers, Patriots all pass-heavy
--49ers and Colts very run-heavy
--To no one's surprise, Seahawks still conservative pic.twitter.com/XdnMyD00YL
— new-age analytical (@benbbaldwin) October 8, 2019

As I’ve noted before, any discussion of pass/run ratios must acknowledge the importance of game script, which is the time-weighted score differential transpiring over the course of a game. The higher a team’s game script, the greater its propensity to run in order to bleed the clock and secure the win. By the same token, a team with a negative game script is more likely to pass in order to attempt a come-from-behind victory.

Which brings us to the 2019 Philadelphia Eagles. In weeks 1-4, as we’ve been repeatedly told, this team faced a 10 point deficit in every single game. Yet, despite having fallen behind early in four of their games, the Eagles, through week 5, have been one the run-heaviest teams in the league.

Recall the Pass Heavy Index, which computes the pass/run ratio relative to expectation given a team’s average game script:

Screen Shot 2019-10-12 at 3.06.47 PM.png

The Eagles rank 23rd in the league, passing the ball 5.5% less frequently than would be expected, given their average game script (0.5). This is their lowest rank since Doug Pederson’s first year as a head coach, with a rookie quarterback. In the last two years, the Eagles have ranked 8th and 10th in terms of situation-adjusted pass heaviness.

Screen Shot 2019-10-12 at 3.08.52 PM.png

Moreover, the first five games of 2019 have been the second most run-heavy five game stretch of Pederson’s tenure. The last time the Eagles were this run-heavy occurred during weeks 3 – 7 of the 2017 season, after Pederson endured considerable criticism from the likes of Frank and Joe from Manayunk following a week 2 loss vs Andy Reid’s Chiefs, when the Eagles passed on 75.4% of offensive plays, Pederson’s most pass-heavy game ever, given the game script (27.8% above expectation).

Screen Shot 2019-10-12 at 3.10.01 PM.png

Does the recent run-heavy approach portend a shift in tactical emphasis, or could it be merely statistical noise? The plot below shows every Eagles regular season game under Pederson’s tenure, with 2019 games in red, labeled with opponents. The regression line shows the league-wide average pass-run ratio; the degree to which a data point is above or below the line reflects the “Pass Heavy Index” for that particular game (positive or negative).

Screen Shot 2019-10-12 at 3.10.56 PM.png

Week 2 (at ATL) and 5 (NYJ) were pass-heavy, when adjusted for game script. Week 1 (TB) and 3 (DET) were more run-heavy than is typical for a Pederson offense. A significant proportion of 2019’s run-heavy tilt is due to the sublime Green Bay game at Lambeau when Doug passed the ball 24.2% less than what would have been expected, given the game script. This game was, by far, the most run-heavy of his head coaching career. There was reasoning behind this anomaly: Mike Pettine chose to keep his defensive personnel in dime and nickel versus the Eagles two tight end sets, allowing Zach Ertz and Dallas Goedert to run block against relatively light boxes. As Jason Kelce pithily explained to Sheil Kapadia, the objective in the game was to put the defense in a bind: “Everything’s just trying to get honest numbers out of them.”

Had Pettine loaded the box with base personnel, you can be sure that the Eagles would have been pass-heavy, particularly with Goedert and Ertz on the field. Removing the unusual circumstances of the Green Bay game, the Eagles -0.5% Pass Heavy Index would rank 17th in the league. Their current league rank, in terms of pass-run ratio, is at least partly an artifact of the game-theoretical nature of Doug Pederson’s offense, which is predicated on running versus light boxes and passing versus heavy boxes.

Per the NFL ScrapR box score app created by The Athletic’s Ben Baldwin, this tactic paid huge dividends. The Eagles at Green Bay had both a higher success rate and expected points added (EPA) per play in the running game, compared with the passing game.

Against GB, he called the most run-heavy game of his career, adjusted for situation. This tactic was successful against Mike Pettine's defense, which dared the Eagles to run. Per #nflscrapr box score app by @benbbaldwin, the Eagles had higher EPA & Success Rate running the ball. pic.twitter.com/bSxRuaqHSW
— sunset shazz (@sunset_shazz) October 12, 2019

Note that a more efficient run vs. pass game is unusual. In weeks 1 through 5 of 2019, as well as during Pederson’s prior tenure, the Eagles had a higher average success rate and EPA passing the ball versus running.

I will close with a prediction: in the following weeks, Doug will unleash Carson. As defensive coordinators begin to recognize that Jordan Howard is quietly efficient running behind Jeff Stoutland’s offensive line, they will increase the number of defenders in the box.

And Pederson and Wentz will take what the defense gives them.

The Kids Are Alright

The following is a guest post by @sunset_shazz.

Carson Wentz’s start to the 2017 season has garnered national plaudits for his stewardship of the Eagles’ league-leading offense. But it being 2017, there lurks a coterie of skeptics who claim his underlying ability is “horrendous” like Blake Bortles or merely pedestrian like Andy Dalton. Even more emphatically, poor Jared Goff was confidently pronounced a bust after one season.

Is it fair to judge a quarterback solely on his rookie year? What about after the first nine weeks of his second season in the league? And how might one systematically evaluate a developing quarterback, relative to historical data?

Let us consider some advanced metrics that are used to evaluate quarterbacks:

Adjusted Net Yards / Attempt (ANY/A) was developed by the great Chase Stuart, and accounts for sack yards, while providing a bonus for touchdowns and a penalty for interceptions. Both Stuart and Topher Doll have shown that ANY/A predicts wins. Danny Tuccitto has brilliantly used confirmatory factor analysis to show that ANY/A is a stable indicator of QB quality.
Defense-adjusted Value over Average (DVOA), the brainchild of Aaron Schatz at Football Outsiders, is a success-based, opponent-adjusted per-play efficiency metric intended to both correlate with non-opponent adjusted wins (descriptive) and to predict future opponent-adjusted wins.
Defense-adjusted Yards above Replacement (DYAR) uses similar success-rate inputs to DVOA, in order to compute an aggregate value for a player (combining volume and efficiency).
Total QBR is ESPN Stats & Information’s proprietary efficiency metric that combines both passing and running contributions, adjusted for game situation, with charting to assign responsibility to a quarterback’s receivers and blockers.

Through nine weeks, the 2017 sophomore class is playing at an extraordinarily high level, as measured by each of these advanced stats:

Please note that nothing herein intends to argue for any of these quarterbacks to the detriment of the others. Though the data presented above is insufficiently precise to draw ordinal rankings, it is unequivocal:

Wentz is good. Goff is good. Prescott is good. All three of these things can simultaneously be true, pace internet trolls.

Some epistemic humility is in order: the first-nine-week sample size is obviously noisy, with varying degrees of luck, opponent quality, team injuries, coaching quality and supporting casts influencing the statistical performance of each QB. Danny Tuccitto warns us that ANY/A stabilizes at 326 dropbacks, and even at that sample size, 50% of the observation represents randomness/luck. Nonetheless, the broad takeaway should be that each sophomore QB has thus far performed at a top-quartile level, judged by a variety of different metrics. Is this good? And how confident can we be that such performance will continue?

Recently, Chase Stuart noted that three sophomores from the same class have not played this well since at least the NFL-AFL merger. Though ANY/A is less context-specific than the other measures, it has the advantage of being transparent and easy to calculate, permitting historical analysis. Stuart compared the first 8 weeks of 2017 for Goff, Prescott and Wentz to full seasons of prior 2nd year QBs. Comparing partial to full seasons isn’t quite neutral, due to the disparity in number of games sampled; we should expect some mean reversion of our reference QBs as sample size increases. Using pro-football-reference’s excellent query engine, I examined the first 9 weeks for each sophomore quarterback from 1999 through 2017. Historical comparisons need to be adjusted for era, due to the enormous change in average NFL passing efficiency over time. To account for this, I divided each quarterback’s ANY/A by the league average for that year. [1]

Top ANY/A vs Average since 1999, sophomore QBs, weeks 1-9

The 76 QB sample set in this study is itself a product of survivorship bias: only those QBs who were successful enough to throw 100 passes in the first 9 weeks of their second year in the league are included. On the other side of the distribution, successful QBs who rode the pine for their first few years (like Aaron Rodgers, Tony Romo or Philip Rivers) are not in this sample. The average age of the sample is 24, similar to our reference QBs.

The three 2017 sophomores are, as Stuart observed, performing extraordinarily well relative to their peer set (all are in the top quartile of the sample). Relative to their era, they are passing with greater efficiency than Tom Brady, Drew Brees, Matt Ryan or Andrew Luck did in their second seasons.

You will also note that the top ranked sophomore QBs include many future hits (Big Ben, Kurt Warner, P. Manning) and a few notable misses (Nick Foles, Derek Anderson). The last column I included is the Career Approximate Value (CAV), which is a (very) rough method developed by Doug Drinen that puts a single number on a player’s total career, encompassing both longevity and performance.

Below, I plotted log Career Approximate Value against ANY/A relative to league average for the first 9 weeks for second year QBs from 1999-2015 (I excluded QBs from 2016-2017 because recent QBs have not yet had sufficient time to accumulate CAV points).

The positive relationship shown above indicates that the first 9 weeks of a sophomore season predicts 37% of a QB’s future CAV. Do note that the correlation is sensitive to a few outliers. The odious Ryan Leaf and Akili Smith are on the bottom left, whereas Foles and Anderson are on the bottom right. I don’t want to ascribe an illusion of precision to this rough analysis – don’t fixate on the exact R-squared number, or the model coefficients. Both sample size and the extremely imprecise nature of CAV make me hesitant to draw definitive conclusions from the data. What is interesting to me is that the same plot using a QB’s full rookie season yields an R-squared of 0.224 – in other words, the first 9 weeks of a QB’s sophomore season tells you roughly 70% more about his future career than his entire rookie season does. Extending this analysis to full seasons since 1970, the R-squared is 0.083 and 0.2348 for rookie and sophomore years, respectively (n=155 & 204). My interpretation of this data: though rookie and second year passing efficiency predict only a small fraction of a quarterback’s career value, the sophomore year deserves 2.8x as much weight as the rookie year, in terms of confidence about predictive power. Rookie performance, in particular, is extremely noisy. One would have been wise to heavily discount Troy Aikman, Donovan McNabb and Terry Bradshaw’s dreadful rookie seasons. Rams fans should take note.

Relatedly, I didn’t find any predictive power when measuring the degree of era-adjusted-ANY/A improvement from rookie to sophomore season. This echoes Vincent Verhei’s study of second year improvement using DVOA. In hypothesis testing, a negative result can be an interesting result.

Quantitative analysis is not the only tool in an NFL researcher’s kit. Film study (though not my sphere of competence) is also valuable. Though Nick Foles had a magical sophomore season, the film showed reason for concern, as my friend Derek Sarley noted. I don’t personally see similar issues with Wentz – both his pre-snap adjustments and post-snap play appear to pass the “eye test”. No, he’s not perfect. Yes, he has flaws he needs to address. But so do all second year quarterbacks.

Moreover, our penchant for treating quarterbacks as static vessels of talent/ability shortchanges the importance of coaching and development. The installation of a new coaching regime in Los Angeles appears to be an interesting natural experiment, in terms of Goff’s maturation. Similarly, we can view Ezekiel Elliott’s probable(?) suspension as an instrumental variable when evaluating Prescott.

All inductive statements are, by their very nature, revisable. We don’t know the future; we can only use informed judgment to hazard a prediction. The false-positive rate for the top 20 QBs in table 2 above is 25% by my count [2], so let’s take that as the “base rate” of failure for the 2016 Sophomore QBs. It is therefore reasonable to expect that two – perhaps all three – of the 2016 sophomores will enjoy successful careers as NFL starters.

Finally, in these impatient times, let us remind ourselves that transcendent quarterbacks do not emerge, fully formed, from the forehead of Zeus. Each of these young, relatively inexperienced quarterbacks is playing the most technically and cognitively demanding position in sports at a very high level. Adjusted for experience and era, their achievements are even more astounding. The evidence suggests that the future of quarterback play is bright. Football fans, rejoice.

Thanks to Eagles fan / Data Scientist Sean J. Taylor for his insightful discussion on methodology. Any errors are mine alone.

[1] PFR’s partial season engine shows results from 1999 onward. Full season results go back before the merger, and also generate an era-adjusted ANY/A+ which uses a “Z-score” methodology, expressed in standard deviations above or below the population mean. My method is less sophisticated, though nonetheless robust.

[2] I excluded the reference QBs, as well as Marcus Mariota.

@sunset_shazz is an Eagles fan who lives in Marin County, California. He previously wrote about 4th down decisions.

The Eagles Aren't Good Enough To Make Mistakes

Despite disappointing results in the last two games, the Eagles are a good football team. Going into this week, they were first in the NFL in point differential and second in DVOA. Now, they remain third-best in the former and should stay near the top in the latter.

Two losses, by a combined score of eight points, do not end the season. But they do show us what kind of team the Eagles are: one that can't afford to make mistakes if they want to compete for the division title.

The truth is that the Eagles don't have many difference-making players. Fletcher Cox and (old but still great) Jason Peters, perhaps. After those two, who can the team count on to consistently win individual match-ups? Carson Wentz has flashes of brilliance. Third down back extraordinaire Darren Sproles is the only explosive play maker on offense.

This roster isn't built to exploit mismatches in talent. It's built on competence. On defense, guys like Brandon Graham, Jordan Hicks, and Malcolm Jenkins form the core, but none of them are keeping offensive coordinators up at night trying to scheme around them. They are good because they do the right thing (most of the time). They won't get you killed and they can succeed within the scheme. Ditto on offense: Jordan Matthews and Zach Ertz are solid starters in the NFL as long as you're not counting on them to be the number one option.

The early season win streak was built on competence in all phases. The defense didn't do anything special with fancy blitzes; it just lined up and got pressure with four rushers. The offense took league-best field position and converted drives into points at the second-highest rate. They did so methodically, not gashing teams with big plays but marching down the field with a mix of efficient runs and short passes (part of the reason Carson Wentz scores so low in Air Yards). Limiting turnovers (to zero for the first three games) and capitalizing on opponent mistakes.

That strategy was effective until this started happening:

As far as I can tell, weeks five and six are the most penalties the Eagles have committed in consecutive weeks since 1989. And those penalties matter. According to friend of the blog Sean Taylor, each additional penalty a team has over its opponent is worth approximately -0.5 points. The Eagles have out-fouled their opponents by 16 in the last two weeks and, surprise, lost by a combined eight points. Add in a couple more unforced errors, like a rookie fifth round pick stumbling out of the gate and a veteran running back fumbling at the worst possible time, and you can see how the Eagles went from 3-0 to 3-2.

Again, this is not to bury them. They are still a good team that should be at least in the race all season. But it's not like teams we've seen in years past that could spot an opponent a three touchdown lead and roar back in the final minutes. There are too few #playmakers and not enough strengths. That means they either have to return to the suffocating competence of the early season—limiting turnovers and penalties, staying efficient on offense, and preventing big plays on defense—or come up with a new way to win... like putting more in Wentz's seemingly-capable hands.

Time To Clear The Air

The following is a guest post by @sunset_shazz.

This is a wonderful time to be an Eagles fan. Jim Schwartz’s Attack Nine defense is rapidly exorcizing the ghost of Juan Castillo. Doug Pederson has rejuvenated an offense that had become stale and predictable under Chip Kelly. And, of course, rookie quarterback Carson Wentz is turning heads across the league, not to mention in the oval office.

Eagles fans, unexpectedly blessed with success, look to the poet Browning to give voice to their collective sentiment:

The lark's on the wing;
The snail's on the thorn:
God's in His heaven—
All's right with the world!

But wait. From his perch at the indispensable Football Outsiders, Scott Kacsmar has some discomfiting news: both Wentz and Cowboys rookie QB Dak Prescott are mere dink and dunkers, with lower than average air yards per attempt (defined as the average distance a football is thrown beyond the line of scrimmage). A low score on this metric is undesirable, in Kacsmar’s view.

The inimitable Jimmy Kempski responded to Kacsmar’s initial claim with a sardonic video rewind post, prompting Kacsmar, in an entertainingly vitriolic rant, to frame this argument as a contest between enlightened, statistically rigorous analysts on one side and straw-manning “numbers are for nerds” egg avatars on the other.

I don’t believe that view is correct.

As Brian Burke has explained:

A statistic that both correlates with winning and correlates with itself would be a reliable predictor of future wins.

First, you want your in-sample measure to have some predictive power in estimating out-of-sample future wins, because, hello, you play to win the game. Second, you want a metric to have some degree of statistical persistence over time, in order to be confident you are measuring a signal (in this case, an attribute of quality quarterbacking) rather than mere noise.

Regarding the latter, Kacsmar notes that in 2015, the correlation between air yards in the first three weeks of the year and the air yards for the entire season was 0.80. Well, that doesn’t seem quite fair, does it? After all, what we really care about is the correlation between the first 3 weeks of the season and the ensuing 14 weeks. Using his dataset, and using the Spearman rank correlation estimator rather than a standard Pearson estimator, which in this case would be considered less robust, I found that the correlation between the first 3 weeks and ensuing 14 weeks last year was 0.60. That’s pretty good, as far as football statistics go. However, do note that within a season a number of other factors surrounding the quarterback are, for the most part, held relatively constant: coaching scheme, strength of running game, defensive strength, etc.

When Chase Stuart examined the persistence of the Air Yards metric from year to year, he found that between 2006 and 2012 for 100 qualifying QBs the correlation between Year N and Year N+1 for Air Yards was 0.34. Both completion percentage and yards/attempt were “stickier” with N to N+1 correlations of 0.51.

Kacsmar, in his FO piece, assembles a smaller dataset (than Stuart, above) which he judges to be salient:

I gathered that yearly data on 21 quarterbacks with at least four years of starting experience, all of whom are still active starters this year except for the retired Peyton Manning. The following table shows their average air yards by year for the period of 2006 to 2015.

The first rule of Analytics Club is to plot your data, so I plotted Kacsmar’s data into a time series chart, in order to visualize the range and variability of the attribute, segregated by quarterback, over time:

Taking Kacsmar’s dataset (which, it is important to note, uses 21 quarterbacks who have experienced some career longevity rather than Stuart’s more comprehensive analysis of 100 QBs), and running a similar autocorrelative N to N+1 analysis, I found that the year-to-year correlation was 0.40. My friend, real-life data scientist Dr. Sean J. Taylor, was generous enough to both replicate my work and provide me with a scatterplot, complete with line of best fit and confidence interval shading:

The autocorrelation statistic, the scatterplot and time series visuals each show the same thing: we are measuring mostly noise, with a faintly detectable QB signal. The attributes I mentioned before—scheme, effectiveness of the running game, defensive efficiency which affects game script—are all likely to change the calculus of decision-making with regard to throwing shallow or deep.

In fact, Kacsmar himself gives us a good reason to doubt the validity of Air Yards in capturing an attribute of QB quality: it doesn’t improve as a player gains more experience. Quarterbacks, like all athletes, typically experience an age curve, reflecting both athletic maturation and decline, as well as the steep learning curve imposed by formidable NFL defenses. Chase Stuart has shown that the age curve for NFL quarterbacks is pronounced. The absence of an “age/experience curve” for Air Yards is yet another red flag.

Air Yards doesn’t appear to measure a persistent quarterback attribute over time, particularly when compared with a conventional statistic such as completion percentage or advanced statistics such as Adjusted Net Yards / Attempt (ANY/A, for which Danny Tuccitto brilliantly used confirmatory factor analysis to verify its validity) or Defensive Yards Above Replacement (DYAR, rigorously developed and tested by Aaron Schatz).

But does it predict wins?

My general model of the production function of football is as follows: runs and passes are inputs; completions and first downs are intermediate goods; points are outputs. Success rate metrics such as Defensive-Adjusted Value Over Average (DVOA), DYAR, and ANY/A are all measures of intermediate goods which are of interest to the analyst because they tend to reliably convert to points. And as Chip reminds us, if you (f__king) score points you are more likely to win.

The scatterplot above shows the relationship between a QB’s average air yards over a season and the points scored by his team over that season. There is no statistically significant relationship between the two measures. Contrast this with ANY/A, which correlates 0.55 with wins. Or DYAR & DVOA, whose parameters were specified in order to predict future wins.

Kacsmar has been careful to note that he isn’t an advocate of maximizing Air Yards; he thinks middle is best. He elaborates in his FO piece:

Generally, air yards are a stat where you don't want to rank at the bottom, because that is where many ineffective passers dwell, including Blaine Gabbert. That preference for short throws often extends to crucial downs, which is why these quarterbacks tend to do poorly in ALEX and attacking the sticks. However, it is not preferable to rank at the very top in air yards either, because that is how "screw it, I'm going deep" players such as Michael Vick, Tim Tebow, Vince Young and Rex Grossman have earned their reputation as inefficient passers.

His claim, if I have understood it correctly, is that quarterbacks at the tails of the distribution are less likely to be successful in future. Our scatterplot above doesn’t show any relationship between the middle of the distribution and success, measured by points scored. But could Kacsmar’s anecdotal observation that “middle is best” be a mere artifact of sampling? If successful quarterbacks have longer careers, the law of large numbers dictates that they will, by mere virtue of larger samples, be less prone to the extremes in Air Yards. Taking a separate dataset evaluating quarterback air yards between 1992 and 2012, and plotting those against passes thrown, one arrives at the following:

You can see that the more passes a given quarterback throws, the less variance he exhibits with respect to his peer cohort. This needs to be examined further, in my view. I admit that I am not familiar with the nuances surrounding various measures of air yards (various observers have different estimates), but a longer, broader dataset would be desirable to plot air yards versus attempts. We don’t want to fall prey to the famous Bill and Melinda Gates Foundation misstep where it was initially claimed that small schools are consistently among the best performing schools, when it was merely the case that small schools experience more variance than larger schools, and therefore disproportionately comprise the tails of the distribution.

Here is the plot of the fourth-grade math scores versus number of students in the school:

The prior two sections showed that Air Yards as a measure is neither statistically persistent nor predictive of success, in terms of points scored. I did mention some alternative, robust metrics, two of which are generated by Football Outsiders. As of Week 3, FO has not applied opponent adjustments to their measures. On a raw Value Over Average and Yards Above Replacement measure, these young QBs have performed in the top quartile over the first 3 games.

Looking merely in the rearview mirror, without making any judgments about the future, they appear to have performed well.

Another measure I have mentioned, Adjusted Net Yards / Attempt (the “adjustment” gives a bonus for touchdowns and a penalty for interceptions, and the “net” deducts sack yards) is a persistent, predictive measure. With a hat tip to the excellent Derek Sarley, I prefer to plot this against completion %, to show both efficiency and consistency of per-play execution (weeks 1-3, minimum 46 attempts):

Once again, the rookies have played impressively: Wentz and Prescott are in the top quartile (4th and 8th, respectively) in ANY/A and the 2nd quartile (13th and 10th, respectively) in completion %.

As Bill Barnwell has noted, the statistics from 3 games tell us very little about how a QB will play in the future. A very small sample size disadvantages a purely statistical analysis; the comparative advantage shifts towards the film analyst. Ideally, one would combine both, but in this case, the stats aren’t meaningfully more robust than mere anecdotes. This is why I disagree with Kacsmar’s adversarial Michael Lewis-style “stats versus scouts” framing; the NFL stats on these two rookies don’t really tell you anything dispositive yet. From a purely Bayesian perspective, the eye test is just as likely as a mere three weeks of quantitative data to meaningfully update one’s priors. I have not yet enjoyed the privilege of watching Prescott, but I’ve seen every Wentz throw; moreover, I’ve seen astute film analysts such as Greg Cosell, Fran Duffy, Jimmy Kempski and Ryan from ChipWagon break his film down. Lastly, as Brent from EaglesRewind notes, one’s priors should be heavily influenced by draft position, which was the NFL auction market’s initial “revealed preference” view of value.

As for me, I’m on the Wentz Wagon. Dan McQuade reasons persuasively that Eagles fans should enjoy this run, because life is fleeting. Memento mori, football fans.

TL;DR:

The early results from the credible advanced statistics, meaning those that tend to be both persistent and predictive, are that Wentz and Prescott have played well in their first three games.
Looking at the numbers alone, a three game stretch is insufficient to give us high confidence that such success will continue in future.
The Air Yards statistic is neither persistent nor predictive, and reflects the aesthetic tastes of one particular writer, rather than a desirable quarterback attribute.

Thanks to Sean J. Taylor for his methodological insight and scatterplot work. Any errors are mine alone.

@sunset_shazz is a Philadelphia Eagles fan who lives in Marin County, California. He previously wrote about Chip Kelly's Oregon bias and other topics, and contributed to the 2015 Eagles Almanac.

Is The Eagles GM Sabotaging Chip Kelly?

I'm starting to think Chip Kelly, our beloved head coach and offensive mastermind, may not be on the same page with the Eagles general manager. In fact, hot take alert here, the GM may be actively sabotaging Chip. Let's examine the evidence.

In 2013, Kelly proved he could take a collection of players drafted by other people and mold them into a successful team. The defense, sure, was a bit rough. But Kelly inherited an offense of Andy Reid's making and turned it into something special. The offensive line dominated, with the left side anchored by two all-pro players, an emerging athletic center, wily veteran at right guard, and a top pick at right tackle. Meanwhile, Kelly's frenetic, quick-strike offensive style was matched perfectly by the dynamic big play duo of DeSean Jackson and LeSean McCoy, who combined for 3,480 yards on the season—including 42 plays of more than 20 yards. Kelly even made Nick Foles, an immobile quarterback with a questionable arm, look like a star.

But I look at the 2015 Eagles, and it seems the GM actively tried to rid Chip of all his best players. He swapped the Foles for Sam Bradford, who costs more and has a terrible injury history. He ditched both of the Eagles' homegrown, in-their-prime dynamic wide receivers for a bunch of unproven youngsters supplemented with empty threats (this week notwithstanding) Riley Cooper and Miles Austin. He flipped McCoy, a shifty home run hitter, for north-south runners, then refused—over Chip's strenuous protests, I'm sure—to put any resources into the aging offensive line that made the whole thing work.

What Kelly's left with is an offense that looks nothing like the type of team he's been successful with in the past. Foles was never a running quarterback, but the current starter can't even execute read option plays for fear he won't survive the next hit. And Bradford doesn't even have the confidence, despite a decent arm, to throw downfield, wasting Chip's proven ability to scheme players open. His twice-a-game realization that there might be open players beyond 5 yards has corresponded with a brief one-quarter offensive resurgence in each game.

The coach probably could have told the GM that the running back position wasn't his limiting factor in the first two years. When defenders shot into the backfield in 2014, McCoy actually made many of them miss and got positive yards. Spending big to get shiny new running backs was much less important than making sure the blockers ahead of them weren't just terrible backups and journeymen. The Eagles GM even had the gall to extend both Allen Barbre and Andrew Gardner, moves which can only be interpreted as a straight up middle finger to his run-first coach.

To be fair, the GM has added talent on the defensive side, bringing it up to average or perhaps even slightly above. But even against weak quarterbacks like Kirk Cousins, the unit's flaws are obvious. While the defensive line is shutting out running backs, giving up the 3rd-fewest yards per carry in the NFL, this is a passing league. The pass rush is nonexistent, with a sack rate of just 3.4%, 5th-worst. Fletcher Cox and Bennie Logan are disruptive run defenders, but can't get to the quarterback. Connor Barwin and Brandon Graham are solid players but not sack artists. That meant that in the final minutes on Sunday, with Washington marching down the field, the Eagles failed to get any pressure. It doesn't help, of course, that the secondary is still suspect.

When you look at all of it together, it's clear that something needs to be done before the Eagles GM torpedoes our head coach's obvious talent. Fire this idiot, I say, and hire someone who knows what he's doing. Heck, maybe give Chip Kelly a chance to take over player personnel. He could probably do just as well.

Can The Eagles Defense Carry The Offense?

Last week, I placed the blame for the Eagles' 0-2 start squarely at the feet of the offense. Despite this week's win over the Jets (yay!), Chip Kelly's favorite unit continued to perform woefully.

Yes, Ryan Mathews, subbing in for DeMarco Murray, rushed for 108 yards on 25 carries. But his numbers hide the fact that there were still far too many negative or no gain rushes (10 total). Between Mathews and Darren Sproles, the rushing game averaged just 3.47 yards per carry, a heady improvement from the prior weeks, but nothing to get excited about. Everyone on the offensive line, including Kelce, Peters, and Johnson, are struggling to run block consistently.

Meanwhile, despite being sacked just once, Sam Bradford played another horrible game. His final numbers were 14 for 28 (50% completion rate) for just 118 yards. One touchdown and zero turnovers, if you want to focus on that. But his accuracy was poor, his ball placement terrible, and he has zero guts to throw the ball downfield, one of the only things that might give the running game enough room to breathe. See more at ChipWagon, as always.

All of which leads to...

The #Eagles offense is regressing. 2013: 6.3 yards per play 2014: 5.6 yards per play 2015: 4.5 yards per play
— Phil Bicking (@p_Red) September 28, 2015

Really bad. So the question is, until the time the offense recovers (assuming that's in the cards?), can the Eagles defense carry the team? And on that front, at least, there are some promising signs. To the stats!

Through three games, the Eagles have given up the 5th-fewest points per drive (1.42), the 9th-fewest yards per drive (26.9) and the 10th-fewest plays per drive (5.6). The run defense has been fantastic—allowing a league-low of 3.1 yards per rush and zero rushing touchdowns. Most important, they've forced turnovers on one out of every five opposing possessions. To keep it going, we'll need more Walter Thurmond ball-hawking and disruption at the line of scrimmage (Brandon Bair sighting FTW).

The worrisome note is that the Eagles haven't gotten consistent pressure on quarterbacks. The defense ranks 8th-worst in sack rate so far. Overall, this isn't terribly surprising. The two-gapping scheme means players like Fletcher Cox are responsible for the run first, then the pass second. Neither Connor Barwin nor Brandon Graham are consistent man-beaters on the outside. And now the top two middle linebackers are hurt. Billy Davis needs to mix in some good blitz concepts to get pressure if this defense is going to sustain itself.

Three games is also quite a small sample size, especially when about half of that time the Eagles faced Brandon Weeden and Ryan Fitzpatrick. Luckily, due to a combination of easy schedule and injuries, the Eagles aren't scheduled to face many top quarterbacks down the stretch. The next three games match up against Kirk Cousins, Luke McCown, and Eli Manning, with Cam Newton as the pre-bye week chaser.

Still, that we're having this conversation at all is a good sign. The defense was atrocious two years ago, and improved to average or slightly above last year. If it can take another leap, that's a huge deal for this team—especially if the offense can't turn it around.

Year Two Begins: An Eagles Offseason Rundown

This time last year, fresh off a sickening 4-12 season and the long-anticipated firing of one of the best coaches in franchise history, we watched as the Eagles spun their wheels in a coaching search. Fresh off being rejected by some of their top candidates, the organization seemed to be turning toward Gus Bradley, although interviews with Bruce Arians, Brian Kelly, and rumblings about Ken Whisenhunt cast an ominous cloud over the proceedings. It wouldn't be until January 16th that Oregon's belle finally came back around and agreed to a surprise contract in Philadelphia.

Chip Kelly's arrival was met with lots of fanfare, and more than a few skeptics. I won't bother to link to those old columns written about the "college coach" and his "gimmick offense," but suffice it to say that no one's a skeptic now. If anything, we're still underestimating the job he did in his first year. Before the season began, I found all 113 teams in Football Outsiders' database that finished 20th or worse in both offensive and defensive DVOA. Those bad teams had an average overall DVOA improvement of +11.9% in their next season. Kelly's Eagles, as it stands now, posted a +37.8% increase, the third-largest jump on record.

But with an early bounce from the playoffs, the long offseason looms and more changes are inevitable. In today's NFL, huge improvement can always be followed by huge disappointment. In my opinion, the Eagles are much more likely to add to, grow from, and improve off of their 2013 success. But that's far from guaranteed. Here's where the team goes from here:

1. Prune The Dead Wood

Being only a year away from a 4-12 season, there are still a number of players on the Eagles roster who shouldn't be around at training camp next year, whether for reasons of age, performance, or both. Let's do a quick roundup of the top targets.

Todd Herremans: Even moving back to guard this season didn't seem to halt the Toddfather's decline. He's not the worst guard in the league, but Herremans was the weakest link on the offensive line and you can't expect him to get better heading into his age-32 season. Maybe you offer a restructured contract and the chance to compete for his job, but guard is one of the more fungible starting positions in the league. Time to see if there's a younger, less expensive backup who can take over.
Trent Cole: The Eagles' longtime DE-turned-OLB passed Clyde Simmons for second place on the Eagles all time sack list with a late season revival. Like Herremans, Cole is heading into his age-32 season and the third year of a contract extension. Despite his resurgence in the second half of the season, Cole never fully adjusted to his linebacker role and couldn't rescue the Eagles' moribund pass rush. We wish him the best, but it's time to move on.
Brent Celek: Another member of the old guard, Celek turns 29 before the end of the month. He proved his worth blocking, made some key receptions down the stretch, and finished with his highest DVOA since 2008. But Zach Ertz figures to replace him more and more as the down-the-field tight end. Celek is probably still a useful player on this team for his versatility, but he's not worth the $4 million salary he's due next year. Prime (Stache) restructure candidate.
James Casey: That was always a one year deal, disguised as three years. Not a bad blocker (and the Eagle could use an H-Back/FB from time to time), but barely saw the field the field for anything else. He probably would rather seek his fortune elsewhere too, although maybe he comes back on a reduced salary as the 3rd TE.
Jason Avant: While Riley Cooper and DeSean Jackson had big DVOA improvement, Avant was one of the few Eagles offensive players to decline this year. He had perhaps his worse season statistically in at least 5 years. Love the leadership, but Avant's not sticking around.
Patrick Chung: Another guy on a fake 3 year deal who should and will be cut posthaste.
Alex Henery: I'll go into depth on this once I can crunch more numbers, but Henery isn't worth keeping for beans.

2. Keep An Eye On

There are difficult decisions elsewhere too. Would be surprised if any are cut this offseason, but the team has reason to examine these relationships closely.

DeMeco Ryans: Leader of the defense and stout run defender who's a major liability in coverage. Turns 29 this summer and has a contract that's easy to do away with. Don't think you cut him yet, but the conversation about the future has to happen.
Cary Williams & Bradley Fletcher: Let's consider the two corners together. Using a broad stat like passer rating, both of these players were middle of the pack. On a good defense, each is probably a solid #2 corner. They're not going to shut down the other team's top receiver one-on-one, but they'll hold their own against most everyone else and get their share of victories. The question is how highly you value that kind of production. Both Williams and Fletcher have salaries that spike substantially in 2014. Do you let one go to make room for Brandon Boykin? Do you keep them both around another year and draft replacement(s)? Could a restructure/extension be on the table?
Brandon Graham & Vinny Curry: Both are young and relatively inexpensive, so they probably get another year in this 3-4 transition. But if the right offer came along, Graham especially could be on the block.
Jason Peters: Nothing big here but he's entering the final year of his contract. Peters was named to his fifth All-Pro team but looked like he lost a step. Eagles hope to already have his replacement on the roster (Lane Johnson), but we can't rule out an extension if he proves he's still capable. Remember, Tra Thomas manned the left tackle spot in Philly until he was 34.
DeSean Jackson: His salary goes up by over 50% in 2014. Hopefully both he and the team are happy with that. Or not.

3. Are They Worth Keeping?

Retaining your own free agents can be tricky, but this year there aren't too many questions. The big decisions come at wide receiver.

Jeremy Maclin: The biggest name on this list comes with a huge "What If?" label following his ACL tear last August. I was on record for a Maclin contract extension before the injury and still want him back. The question is how healthy he is and what kind of money he's looking for. The market for wide receivers isn't especially deep, but you don't often see guys get big money coming off knee injuries. A one-year deal with the Eagles might make sense for both sides.
Riley Cooper: The wide receiver went from racist problem-child to key contributor quickly. He has size, blocks well, and adjusts to deep balls better than most. But on a good team he's a 3rd or 4th wide receiver, and I wouldn't pay him more than that because he'll never be someone who can consistently beat single-coverage. In other words, let him test the market (where there may not be much interest) and only resign him at a backup rate.
Michael Vick: If he resigns himself to taking a paycheck as a backup, there are worse places to do it than Philadelphia. But maybe he's looking for one last shot at a starting role, and he could get it with the Jets, Jaguars, or somewhere else.
Donnie Jones: Fantastic job this season. Sign the man.
Nate Allen: Actually became the best member of the safety corps, which just shows how bad the safeties were. Let him walk.
Kurt Coleman: Bye.
Colt Anderson: Never going to be a competent safety, but still a great special teams player. Bring him back and let him compete.

4. Seek Improvement From Youngsters

The last two drafts have been tremendously successful for the Eagles, and they have more than a handful of young players who are forming a new backbone to this team. Their improvement (or decline) will largely decide how the team does in 2014 and beyond. It will also determine who deserves contract extensions and who might not be worth the trouble.

On defense, the young studs are Brandon Boykin, Mychal Kendricks, and Fletcher Cox. They've all shown flashes, but where is the ceiling? Meanwhile, Bennie Logan and Earl Wolff will be given every opportunity to win starting jobs, but both need to make big leaps this offseason.
On offense you're looking at Lane Johnson, who had a successful rookie season by mostly avoiding making news. All eyes will be on him next year, to see if he can take over at left tackle after Jason Peters. Zach Ertz also seems inline for a big year as the featured tight end in 2014.
Nick Foles' offseason matters the most. I'm not convinced he's a franchise quarterback, but he played like one in 2013. Defenses will study him intently next year, and he's unlikely to maintain his fantastic interception rate. Can he improve in other areas to maintain an edge? Foles has earned the benefit of the doubt, but we will find out.
As for backups: guys like Bryce Brown, Chris Polk, Dennis Kelly, Damion Square, Najee Goode, and Matt Barkley need to prove they're worth trusting. Does Casey Matthews get another year? What about Curtis Marsh, Roc Carmichael, and Julian Vandervelde? Lots of question marks.

5. Identify Obvious Roster Holes

Last offseason, the Eagles had gaping holes across the defense. They drafted a smattering of young players (Wolff, Logan), and added low-to-mid price veterans (Barwin, Williams, Fletcher, Chung, Sopoaga). Due to the relative success of that plan, there aren't as many problem spots as there were a year ago. Here are the main starting spots that need help.

Safety: It's easy to imagine a future where Wolff is the only guy left from last year, and he's certainly not a sure thing. Major upgrade still needed here.
Pass Rusher: The Eagles need to generate more of a pass rush. Some of that could come from improvement along the defensive line. But a dynamic pass rushing outside linebacker might make the biggest difference of anyone on the team.
Wide Receiver: At the very least you bring back Riley Cooper, but ideally you're looking at someone more dynamic across from DeSean. Plus, a new slot receiver to replace Avant would be nice.
Kicker: Forget field goals for a second. You need a kicker who can consistently reach the end zone on kickoffs.
Nose Tackle: Logan may be the guy, but my lasting memory of him from 2013 will be the Saints blowing him off the line of scrimmage.
Guard: If you jettison Herremans.

6. Plan For The Future

While you're logging the problems the team faces right now, it's also time to take stock of the future. Where will the team have holes a year or two from now?

Cedric Thornton is an exclusive-rights free agent (meaning he can't negotiate with anyone else). One of the few eligible players on the roster probably worth a long term extension.
Can't count on 30-something offensive linemen to stay healthy in the short term or sustain performance long term. Grab more depth on the offensive line.
Draft a quarterback. Always draft a quarterback.
Kendricks looks like a keeper, but Ryans may not have more than a year left. Time to get another young middle linebacker.
Boykin is probably a long term answer at cornerback, given his stellar performance in the slot. But tied to the Williams & Fletcher questions above, drafting more corners should be high on the list.

7. Find Difference-Makers In Free Agency

Building through the draft is great, but being active at the top of the free agent market is also important. I'm not talking about bringing in another Nnamdi Asomugha, but the Eagles will have plenty of cap space and few in-house players to spend it on. Howie Roseman and company must identify a few key players who can come in and not only fix problem spots in the short term, but are also good long term bets. Some candidates...

Jairus Byrd: If the Bills safety makes it to free agency, he'll command top dollar. You'd rather he wasn't going into his age-28 season, but he's an All-Pro caliber player still in his prime who would immediately lock down one of the Eagles' safety spots.
TJ Ward: Fellow second-team All-Pro safety may be slightly less expensive than Byrd. He's also nearly a year younger. Would be a great get.
Eric Decker: Again, I'd rather just bring Maclin back. But Decker is a much better version of Riley Cooper (albeit at a significant markup). There's also the underachieving Hakeem Nicks out there
Julian Edelman: Probably can go cheaper in the Avant-replacement department, but there aren't many better slot guys when healthy. Maybe Chip wants more upgrade here.
Brian Orakpo: Who knows what's going on in D.C. these days? Elite pass rushers don't come cheap, but Orakpo would fit right into a key role on the Eagles defense.
Donald Butler: If he makes to the open market, you could grab San Diego's young stud middle linebacker and jettison Ryans earlier than planned.

8. Refine The Scheme

To be fair, this is more than one-eighth of the offseason agenda, but it's the one that's least conditional on specific player debates. No matter who the Eagles bring back and who they add, the coaches have to adjust and prepare for a new season.

Chip's offense lit up the league, and ended up second only to Peyton Manning's Broncos on the DVOA chart. He'll be on every defensive coordinator's To-Do list this offseason. I have confidence in the head coach, since he's shown the ability to adjust his offense to two quarterbacks with opposite skill sets. But Kelly needs to stay a step ahead. Defenses stymied some of his schemes, and in some areas he became too predictable by the end of the season (see Cowboys and Saints defenders reading nearly every screen). New weapons will help on that front, but so will new wrinkles. I'm looking forward to seeing what he draws up in 2014.

When you switch to defense and special teams, it's worth noting that the team finished in nearly the same place as 2012 according to DVOA. The defense improved slightly, but there's still a long way to go. Patient, accurate quarterbacks (a species the Eagles were lucky to avoid for long stretches of the season) tore this defense apart with its weakness in coverage down the middle, complete lack of pass rush, and horrible missed tackles. Again, personnel was often at fault there, and this was only year one of a defensive scheme shift. But the scheme can't be as predictable going forward either. Time for Billy Davis to prove he can lead the unit to a renaissance.

Eagles-Patriots Preseason Thoughts: This Offense Is Going To Be Fun

I'm not fretting about Fletcher Cox. As Derek Sarley laid out quite plainly, the problem on those first few run plays was much more about spacing in the new 3-4 defensive lineup. The bigger problem was Trent Cole, who looked totally out of place as a stand-up linebacker. Maybe he'll get better, but I wouldn't count on it. The sample size wasn't large, but I thought Brandon Graham looked a lot more comfortable out there.
In nickel packages the Eagles tended to switch to a four-down linemen look, and Cole looked like his normal self there. Back in April I suggested that the coaches keep Cole as a down rusher -- even consider starting him at 3-4 defensive end. That latter option is probably off the table now that Cole has slimmed down for his OLB role, but I wouldn't be surprised to see him has a dedicated pass rush specialist in exclusive four-linemen looks before long.
As a broader point, the 3-4 defensive transition is going to be rough. Not only do some of the players not fit into their defined roles, but the spacing issues will probably continue. Good offensive coaches will exploit this inexperienced front, and Mychal Kendricks and DeMeco Ryans are going to get mauled at the second level.

On the touchdown pass, Sheil Kapadia says: "Vick said [DeSean] went deep because the Patriots had a single high safety." Jackson's ability to stretch coverage is even more necessary now that Jeremy Maclin is out for the year. If can't keep safeties honest, the run game and short passes become difficult.
Zach Ertz looks like he needs some serious work. He's not a speedy receiver (only 4.68 second 40 yard dash) and he looks totally lost blocking. Here Ertz is at the top of the formation letting Jerod Mayo (admittedly a good linebacker) get by him without so much as slowing him down. While the offensive line is getting a good push up the middle, Mayo comes in off the edge unblocked and makes the tackle:

Here's a cool play: a zone-read design where the quarterback is looking at the defensive tackle instead of the end. It's the Eagles' fourth play from scrimmage, with Vick deciding whether to hand off to Chris Polk or keep it himself. The typical zone-read we've seen in the NFL so far (and we also saw from the Eagles on Friday night) involves letting the defensive end come upfield unblocked. If he goes for the QB, you hand it off. If he goes for the RB, the QB keeps it. Same idea here, but Vick is reading Vince Wilfork at defensive tackle. If he had sprinted to his left to get Polk, Vick would have had a huge hole up the middle. Because he stayed in his lane, Polk gets the hand off and has two double teams to run behind on the right (click to embiggen):

Just as I was drawing this play up, Chris Brown posted an extensive review of Chip's play calling, including this one (with a gif). You should definitely check that out.
Brown talks about "packaged plays" as well, and Sheil has a glorious medley of screen caps on those run-pass options.
However, my favorite play of the night was the one below. What looked like a zone-read play to the left was really a play-action rollout to the backside. Vick has a clear run-pass option on this play and it's killer for the defense. This is something Foles doesn't present -- a dangerous running threat out of the backfield. The Patriots defenders who weren't sucked in by the play action aren't sure whether to converge on Vick or cover their receivers, so neither happens. Easy 19-yard completion to Riley Cooper:

Lane Johnson looked athletic and powerful. Sheil had good shots of him pancaking defenders and getting to the second level: here and here.
Fellow Eagles Almanac scribe Dan Klausner is trying to convince me that Chris Polk is ready for the big time. I'm open to the idea, but haven't seen it yet. Certainly he is the better pass blocker (see Sheil's screencaps here), but Bryce Brown is a much more dangerous weapon. Watching him explode through holes or grab passes out of the backfield, it's obvious that Brown's someone you want to have the ball. Perhaps it's a silly hypothetical, but I can't shake the feeling that Brown would have exploded through that hole for a first down on the Wilfork zone-read.
Nick Foles moved the ball very efficiently in the Eagles' first real up tempo test. See more from Jimmy Kempski.

For much much more on everything Chip Kelly and the Birds, buy the Eagles Almanac!