Interception numbers explain why Dom Capers’ Packers defense is struggling

“We understand that Jay is excited about his new weapons, but it’s the same-old Jay. We don’t need luck; Jay will throw us the ball.” - Charles Woodson, September 13, 2012.

Dom Capers has been running defenses for a long time, and while Dom’s defenses haven’t been as bad as people think, they have been putrid more than they’ve been elite. Moreover, Capers’ first few defenses with the Green Bay Packers were among his best, ranking 2nd in both 2009 and 2010 by DVOA. His more recent record isn’t nearly as good.

Since the Super Bowl season of 2010, the Packers have had a few good defensive units. They had one in 2012 when Charles Woodson made the statement above, but they have not been a top 5 unit and when they’ve been bad, they’ve been really bad. It may seem cliched to say that the league has passed Dom Capers by, but statistically speaking, the league has passed Dom Capers by, and it’s almost certainly time to move on. The fact is that the Capers defense is built for an NFL that no longer exists, and hasn’t for quite some time. In fact, the Capers defense has actually worked as intended almost every year, but because of the way modern offenses work, it simply doesn’t matter.

The Capers Philosophy

Dom Capers had a sound philosophy based on sound mathematical principles. Capers’ defenses focus on preventing big chunk plays. The goal is to make an offense execute a high number of plays to move down the field. As the offense is forced to run more plays, the odds of them committing errors or turnovers increases, and if you create enough turnovers, sacks, bad penalties, etc, you will have a great defense.

X = Interception Percentage

Y = Number of offensive plays run per score.

If Y is high and X is high, turnovers are extremely likely.

From 2007-2011, average X = 1.982%

In the Capers era the Packers have been very good at intercepting passes. In fact, the only year of the Capers era (aside from 2017) in which the Packers did not finish in the top 10 in interceptions was 2013, where they only managed 11. In short, the Packer defense is designed to get interceptions, and it almost always does so at a well-above average level. Just last season they were tied for fourth in the league. The problem is, being tied for fourth in the league isn’t what it used to be, as you can see below:

A few notes about this table:

• In 2011, the Packers allowed the most yards in the NFL
• In 2013 and 2015, the run defense was 29th in the NFL in yards per carry
• 2017 stats are through seven games

The Cooterization of the NFL

Matthew Stafford used to throw a lot of interceptions. From 2011-2015 his interception percentage was never under 2.0 and in 2013 it hit a solid 3.0. In that same time period Aaron Rodgers only exceed an interception on more than two percent of his passes once, in his injury-shortened 2013 campaign. Then in mid-2015, the Lions fired offensive coordinator Joe Lombardi, replacing him with Jim Bob Cooter. Cooter basically eliminated high-risk passing from the playbook, and as a result Stafford’s picks plummeted to 1.7% of passes in 2016, while he also had career best completion percentage marks in 2015 and 2016.

Moreover, this less dangerous, more conservative approach hasn’t really hurt Stafford’s efficiency, and while his yards per completion is down in the Cooter era, his yards per attempt are consistent with career norms. The Lions and Matthew Stafford are more boring now than in the glory days of Calvin Johnson, but they’re about as efficient at moving the ball, with fewer mistakes.

Last season Vikings quarterback Sam Bradford set an NFL record for completion percentage while basically eliminating mistakes, throwing only five picks all season (an INT% of just 0.9%). Those completions tended to be short and the offense overall was somewhat limited by the dink and dunk approach, but they didn’t make mistakes and relied on their defense.

The trend in the NFL is to take drastic steps to reduce interceptions. A decade ago, in 2007, the league as a whole averaged just over two interceptions a game, with 534 total picks thrown, but that number has been steadily dropping over time. Five years later in 2012, the league threw just 468 picks (1.83 per game), and after a brief uptick in 2013, that number has plummeted further. The 2016 season saw just 414 interception, or 1.62 per game, and while the 2017 is up a bit at 1.69, it would still be the second-lowest total of the last 6 years, on pace for 435.

With teams taking active steps to limit interception opportunities, it becomes harder to base a defense on the concept of takeaways. In Capers’ first 3 years as defensive coordinator in 2009-2011, the Packers picked the ball off 30, 24, and 31 times, leading the league in 2009 and 2011 while finishing second in 2010. Those totals are frankly ridiculous, and would be unheard of today. In 2012, the Packers intercepted 18 passes, which put them 8th in the league; fast forward to 2016 and just 17 picks put them in a tie for fourth. The three teams that led the league in 2016 (Kansas City, San Diego, and Baltimore) all tied with 18. What led the league in 2016 would have put you around 13th from 2009-2011.

Going conservative with regard to picks does have a cost for offenses in that passes tend to be shorter, drives tend to be longer, and big plays tend to be fewer, but most offenses are still as efficient as they were in more carefree days. Teams are counting on the ability to hit a higher percentage of short passes to repeatedly move the sticks, something the Capers’ defense actively tries to encourage. If your defensive philosophy is encouraging an already existing offensive trend, you may have some difficulties. The fact is that while turnovers are still huge, game-changing plays, a modern defense needs to be able to force punts to be successful. A “bend-but-don’t-break” strategy that allows a careful team frequent trips to the red zone is doomed to fail.

Interceptions in the modern NFL are almost always a result of a team consistently leading and forcing their opponent to take risks. The difference between the league leaders in 2016 (18) and the 21st-ranked teams (Seattle and Houston with 11 each) is so small that luck is almost certainly an enormous factor. Good teams still get turnovers when given the opportunity, but they are a byproduct of forcing offenses to make difficult plays, not simply causing them to run more plays, and giving up short gains at the expense of preventing big ones will get you killed.

Dom Capers either needs to change his basic philosophy or retire. The Seahawks, and the famous Legion of Boom, have not finished outside of the top 5 in defensive DVOA in the last 5 seasons. They had a dominant 2013 season in which they picked off a league-leading 28 passes, but the picks have since dried up. In 2014 they finished as the 18th-ranked team in interceptions with just 13. In the 2015 season they had only 14. Last season, they were all the way down at 21st in the league with just 11 interceptions, but despite the turnover well drying up, they remain a top-5 defense because they can stop teams. They get after quarterbacks, create long down-and-distance situations, and get off the field on 3rd downs. Interceptions are no longer the cause of a good defense, they are the result.

Interceptions made the Packers dominant on defense at the start of Capers’ tenure, but the days of defenses forcing mid-twenties interceptions is over. His ceiling is “good,” and that’s not good enough.