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:

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.

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).

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).

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.

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:

Chart courtesy Sean J. Taylor

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. 

Chart courtesy Sean J. Taylor

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.

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.

Why Nick Foles Is Better Than Ever (But Can't Stay This Good)

I call him SuperNick. The man who threw seven touchdown passes in little more than three quarters of play deserves such a cartoon moniker. But how did "one of the better backups in the NFL" become in one afternoon the guy who plays what "might have been the best three-quarters of a game we've ever witnessed"?

The simple answer is, he didn't. With the notable exception of four horrendous quarters against Dallas where he looked like he sustained a concussion before he ever got to the stadium, Foles has looked good all year. Andy Reid and Marty Mornhinweg may have the quarterback guru reputation, but Chip Kelly's offense has been much friendlier to QBs than he gets credit for. Why? Because his spread-option, up tempo, zone read running attack forces opponents to pick their poison. Kelly has repeated versions of this quote for years:

"They can't defend it all. I'm really happy with how we threw the ball. If you're going to devote nine guys and try to stop the run, God bless you, and we'll throw it."

Since early in the season, defenses have made their choice: plug the box with seven or eight players and keep just one safety back deep. That often leaves man-to-man coverage on the outside against DeSean Jackson and Riley Cooper. Those are golden matchups for a quarterback, but the Eagles haven't executed. As Sheil Kapadia wrote after the Cowboys game, "An average QB performance likely would have yielded 300+ yards and a score in the 20s." Unfortunately, Foles couldn't make that happen. Neither could Matt Barkley, as Derek Sarley showed last week.

Jump ahead to the Raiders game, and Foles finally started taking advantage of those one-on-one matchups, just as he did against the Buccaneers. Fran Duffy diagrammed all 7 TDs, and over and over you saw Cooper and Jackson beating man coverage -- and passes actually finding them. The gains were comical. Check out how Foles' numbers on long passes differ from last year (stats courtesy Pro Football Focus):

To start with, Foles is attempting about 50% more long passes than he did with Andy Reid at the helm. That's a big jump. His current rate of 16.1% is near the top of the league, after placing in the bottom half last season. This change is entirely about the offense; Michael Vick has also seen a spike in his deep balls, bringing him back to 2010 levels after declines the last two years.

But where things start to get crazy is the long ball effectiveness. Foles completed only 36% of passes 20 yards or longer in 2012. That's up to nearly 53% so far this year. Long ball completion percentage is a huge indicator of success. Look at the list of QBs who posted 48% or above last year: Kaepernick, Rodgers, P. Manning, Newton, Griffin, Brees, Wilson. That's elite territory.

Can Foles keep that completion rate up? Unclear. While there may be some regression to the mean, I'm actually bullish on this front. Kelly's offense seems to be giving his QBs a boost. Vick has also seen a double-digit jump in 20+ yard completion rate, so Foles' numbers may not be an aberration.

Touchdown and interception rates are another matter. Foles is averaging an insane four TDs for every ten long passes he throws. Eight out of his ten completions at that distance have gone for six points. He also has no interceptions at any distance all year -- the only quarterback with more than 75 passes who can say that. (No fumbles either.)

Even if the completion percentage stands, those most certainly won't. Last year, RGIII led the league in touchdown rate on passes of 20 yards or more -- at only 19.4%. Even if defenses don't significantly adjust their coverage schemes (although I expect they'll have to back out of the box more now), Foles simply can't count on the type of luck he's had so far with defenders falling down, receivers wide open, and more. He also eventually will start throwing interceptions. Last year he threw them on just 1.9% on all throws, but Football Outsiders' adjusted interception rate showed a more pedestrian 4.2% after accounting for defenders dropping would-be picks.

The first takeaway here is that SuperNick's current outsized numbers will almost certainly come back to Earth. He may be good the rest of the year, but he won't be that good. The second takeaway is more important, though. Foles' improvement is only over a small sample, but it may not be an anomaly. Kelly is putting his quarterbacks in a great position to succeed, and when defenses change to prevent that, it will only give McCoy more room to run. If the Chip's scheme looks this good with competent QB play from a limited upside guy like Foles, think about what it might do with a true top-tier talent at the position.

Why The Foles-Vick QB Controversy Doesn't Matter

As many of you may remember, or at least can determine by the site headline above, this blog was founded on a quarterback controversy. Not to be hipster about it, but that one, between Donovan McNabb and Kevin Kolb, mattered a lot more. It was about the future of a franchise, turning over the reins to a player who had been groomed for success and jettisoning the veteran who led the team for a decade.

This one between Michael Vick and Nick Foles pales by comparison -- largely because I don't think the outcome matters much.

Let's look first at the performance this season. Who gives the Eagles the best chance to win against the Cowboys on Sunday (assuming Vick is back to 100% health)? Again, in broad strokes I'm not sure it matters. Chip Kelly has shown a remarkable ability to adapt his offense to fit the strengths of his quarterback.

With Vick starting through the first five weeks, Kelly called a heavy does of read-option. I've never seen a running game perform as well as the Vick-LeSean McCoy combo. They helped the Eagles to a dominant #1 rank in rushing DVOA. Vick has also been solid through the air. He's only completing 54% of his passes, but his interception rate so far is a career low (1.5%) and his yards per attempt a career high (9.0).

With Foles at the helm on Sunday, Kelly pared down the option plays in favor of straight power runs. McCoy finished with 116 yards on 25 carries, down from his rushing average in the previous games. Less explosive but still effective, those runs set up short passes that catered to Foles' accuracy. The second-year QB ended up with the best DYAR performance this week. As Football Outsiders acknowledged, that came with a lot of help from his teammates converting dump offs into long gains -- and Foles completed a much higher percentage of long balls than he did last year. Still, a great performance.

My gut reaction, based on the caveats above, is that Vick is still the better option to win right now. But the difference may be marginal. The offense ranked 5th in overall DVOA through the first five games. Then with a different QB, it put up 31 points against the 3rd-best DVOA defense. Regardless of who starts under center (or in shotgun), poor performance on defense and special teams remain the limiting factors for this team in 2013.

As for 2014 and beyond, neither Vick nor Foles is the answer. Vick is 33, constantly banged up, and has no more improvement left in him. Foles is young but limited. Not only is he largely immobile (QB draw aside), but his passing skills rely on the low upside combination of poise and short passes. His arm is weak and interception rate last year was bouyed by drops. Long term, that's not a combination worth investing in.

What the Eagles need will likely come in the 2014 draft: a high-upside passer and runner who can orchestrate the entirety of Kelly's offense for years to come. Whether that's a Marcus Mariota, Tajh Boyd, or even Johnny Manziel, the next generation Chip QB hasn't arrived yet. Arguing about who should start on this year's transitional squad is a waste of energy.

Chip Kelly Is Already Two Steps Ahead Of NFL Defenses

In his Sunday training camp rundown, Sheil Kapadia mentioned one play the Eagles ran that caught my eye:

The Eagles run what initially seems like a read-option play, but instead of taking off, Vick unleashes a pass to McCoy, who is out wide.

It's just one small play in a whole day of practice, but the implications are much greater—it shows that Chip Kelly is a couple steps ahead of the NFL defenses he's facing. Opposing coaches have been studying up on the zone read, trying to get a handle on stopping it before it expands even more widely this season. Last week, Chris Brown wrote a fantastic piece on that quest, as did Greg Bedard—who had Stanford's Derek Mason take him through the learning process NFL coordinators are facing.

If you read those articles, you'll understand the difficulty inherent in facing an offense capable of running the read option. You'll also see suggestions that NFL defenses can catch up if they adopt the "scrape-exchange" and other policies that expert college teams have worked on. But while coaches are trying to teach their defenders how to fight back, Kelly is bringing in a host of new ideas from the college level, most notably turning the "regular" zone read we've already seen from Robert Griffin III and Colin Kaepernick into a triple option attack.

Brown wrote about these variations back in 2009. He described how the triple option off the zone read is easy to do with a third runner in the backfield, but also how bubble screens and other pass options can be even more deadly and unpredictable way to keep the defense honest. Here's Fishduck on Kelly's use of the bubble screen: 

Most of what Fishduck talks about in the related article is using the bubble screen as a constraint play to keep the defense honest. Many times, the read is taking place before the snap, and the zone read is little more than a play-action pass. But other times, as in 1:40 in the video, the quarterback is reading two defenders. After pulling the ball based on the defensive end crashing down, he sees the outside linebacker coming at him too. Instead of taking a loss, the quarterback has a third option to throw a quick bubble pass.

Kelly actually talks about that exact play in this video (at 2:15) with Urban Meyer:

The key, as you learn from Fishduck above, is that a third pass option added to the zone read makes it that much harder to defend. The defense can't load defenders into the box without the quarterback making an easy switch to the outside pass (without even needing to audible). Moreover, even if they execute the scrape-exchange properly and get a defender on the quarterback keeper, he still has an option to throw. 

Nothing about this is fool-proof, and a sound defense can slow down the triple option threat (or keep it to dink-and-dunk down the field). But NFL teams still trying to catch up to last year's version of the zone read are going to be falling down if they don't adjust to what Kelly is adding on to it.

Also: Buy the Eagles Almanac 2013 if you haven't already! 

Putting the Stopwatch on QB Release Times

Fantastic work by Jimmy Kempski (two links in two days)​. He timed every throw by Michael Vick and Nick Foles last year:

The Eagles have a very dynamic set of skill position players. When your QBs are holding the football for 2.87 seconds on average, you're essentially asking the QB to do a large portion of the work in your offense. That is not ideal when you have one aging QB that is in steep decline and another that was a rookie 3rd round pick. The quicker you can get the ball out of your QB's hands and into the hands of the guys who should be making plays, the better the offense will be.

Definitely check out his full breakdown. You can even tell when the Eagles decided it was time to change things up for Vick (as confirmed by All-22 tape).

Putting Nick Foles' Play in Context

Last week, Greg Cosell of NFL Films told Tim McManus that film study showed how Nick Foles was making progress week by week:

“I think there has been a little bit of progression,” said Cosell. “Early on, like a lot of young quarterbacks, he was a primary read guy. He was making predetermined throws, what I like to call, ‘I am going to throw that ball out of the huddle’ where the defense almost becomes irrelevant. I thought this week [against Dallas] Foles had much better pocket command and was much more decisive with his reads and throws and I think the game plan helped.”

With Foles' leading a come-from-behind victory Sunday against the Tampa Bay Buccaneers, that trend seems to be continuing. While I may have been annoyed that the Eagles won the game, squandering a chance to get a better draft pick, Foles' play has been a bright spot. He hasn't looked perfect -- far from it. But he's looked like a quarterback that belongs in the NFL, an improvement from his first game or two. On Sunday he drove the Eagles down for a touchdown to win the game on the final play, a play he called. (More important: he proved that even as one of the slowest football players of all time, by my estimate, he can scramble for a TD.) That's a major boost.

Still, let's step back and put his season so far in context. Here's how he's doing against his peers:

Foles' first handful of games have been a mixed bag compared to his fellow rookies. He has completed about the same percentage of passes, but at a yard lower rate. He has thrown fewer interceptions, but also has fewer touchdown passes. Steady but not explosive jives with what we can see on the field. He hasn't looked like Luck or RGIII.

I did isolate just the performance over the last two weeks, though, to capture Foles' improvement. It's obviously a small sample size, but that line looks much more promising. His touchdown percentage is up, as is his yards per attempt -- without sacrificing completion percentage. The goose egg in the interception column is misleading; defenders have dropped at least two easy picks. Still, there's a clear uptick in performance that puts him in line with or slightly better than other rookies.

If Foles can keep this up for the remainder of the season, it will be a strong case for giving him a shot at the full job in 2013.

Photo from Getty.