Did you know the Chargers started five different centers in 2014, or that the Ravens placed five cornerbacks on IR? Part II of our 2014 AGL study looks at injuries by unit.
12 Aug 2014
by Scott Kacsmar
Yesterday we looked at how quarterbacks handled pressure in 2013. Now we turn our attention towards how defenses fared in creating that precious pressure. There were record-setting offensive numbers, but defenses did have the highest league-wide pressure rate (24.7 percent) in the last four years. While most pressure does not result in a sack, the league's sack rate was 6.7 percent (actually 6.66 for those with an interest in the occult). That's the highest since 2005.
Sacks are always glorified, but it's great to have the other pressure stats for a fuller view of a pass-rush's effectiveness. Robert Mathis (19.5) and Robert Quinn (19.0) had the most sacks in 2013, but Quinn was second in the league with 36 quarterback knockdowns (sacks plus hits). Mathis had 22 and J.J. Watt led everyone with 47. Quinn (43.0) also finished ahead of Mathis (33.3) in quarterback hurries. In the future, when someone's voting for an All-Pro team, an All-Decade Team or the Hall of Fame, hopefully this data carries more weight than the old way of just looking at sack totals. Maybe a high-motor guy like Kevin Greene would already be in the Hall of Fame if we had charting for his career that showed he had a ton of hurries, which can still be very effective at disrupting an offense.
Individual stats like hurries and knockdowns (plus much more) are included in the Football Outsiders Almanac 2014, available here. We are now focusing on defenses at a team level with this next table, which only includes regular-season plays. These are all pressure plays (sacks, hurries and forced scrambles), so aborted snaps and coverage scrambles/sacks are not included. As with DVOA, the one in-play penalty we include is Defensive Pass Interference. Recall a negative DVOA means above-average efficiency. Defenses are sorted by descending pressure rate. Rankings in DVOA with and without pressure are both done from best (No. 1) to worst (No. 32). The "Difference" section ranks defenses by descending pressure drop. The higher the ranking, the more that defense relied on pressure for success.
|Defense||Plays||Pct Pressure||Rk||with Pass Pressure||without Pass Pressure||Difference|
|Defense||Plays||Pct Pressure||Rk||with Pass Pressure||without Pass Pressure||Difference|
The drop in DVOA when quarterbacks were pressured (-107.9%) was nearly identical to 2010 (-108.2%) and 2011 (-110.9%), leaving 2012 (-119.6%) as the year with the most effective pressure (also the lowest rate at 20.2 percent).
Buffalo was the only defense to have a negative DVOA (-0.3%) without pressure, which makes some sense given then-defensive coordinator Mike Pettine is a Rex Ryan disciple. In 2012 the Bills had the seventh-worst DVOA (45.6%) without pressure, so that was a huge improvement. The Bills had the smallest pressure drop, but how can they sustain this success with Pettine in Cleveland, Jairus Byrd in New Orleans and Kiko Alonso on injured reserve? Kyle Williams and Jerry Hughes had double-digit sack seasons, but never had more than 5.5 sacks in any previous season. Not a ton of optimism here for a great 2014 defense when so much of the foundation has shifted.
Atlanta was the opposite of Buffalo: worst DVOA without pressure and the largest pressure drop. Making matters worse is the fact the Falcons had the fourth-worst pressure rate in 2013. This defense needed to get to the quarterback to have any success. Without pressure, the Falcons allowed a league-worst 8.7 yards per play. Some questioned letting John Abraham go to Arizona, where he did quite well at 35. Osi Umenyiora was not nearly as effective replacing Abraham, and the defense was struck hard by linebacker injuries.
The strength of the 2013 Carolina Panthers was their front seven. They covered up a so-so secondary and had the league's best DVOA with pressure, but you may be surprised to see they still finished sixth without pressure. The only teams to rank in the top 10 in DVOA with and without pressure were Carolina, New Orleans, Arizona, Seattle and Cincinnati.
The NFC defense to best fit the mold of "secondary is toast without pressure" was St. Louis: fifth with pressure and 21st without for the second-biggest pressure drop in the league. Of course the Rams added to the front seven with Aaron Donald in the first round, but the young secondary should be a little better this season under Gregg Williams. Good riddance to Cortland Finnegan with his 34 percent Adjusted Success Rate.
Cincinnati has done well under defensive coordinator Mike Zimmer the past few years without a heavy reliance on pressure. Zimmer will have his work cut out for him in Minnesota after the Vikings ranked last with pressure and 24th without. The oddest set of rankings may belong to Tennessee: 30th with pressure, but 11th without. Jason McCourty is a solid cornerback, but Alterraun Verner shined with a breakout year. He left for Tampa Bay and the Titans are now using Ray Horton's scheme, which has produced fairly equal rankings in the last three years with Arizona (2011-12) and Cleveland (2013).
In fact, the only teams to have the same rankings with and without pressure were Cleveland (23rd) and Houston (28th). We can expect big changes there with new head coaches and top-tier prospects. Pettine will have a cornerback duo of Joe Haden and Justin Gilbert to go along with a developing pass-rusher like Barkevious Mingo. The Texans, of course, added Jadeveon Clowney with the top pick, creating a potentially nightmarish duo with J.J. Watt.
We questioned how consistent pressure can be for offense, so how well does it correlate on defense when that side of the ball is notorious for more variation from season to season? We ran the same four year-to-year correlation tests on 2010-13, but this time it was for 32 teams instead of 27 qualified quarterbacks.
|Stat||Offense Correlation||Defense Correlation|
|DVOA with pressure||0.18||0.11|
|DVOA without pressure||0.58||0.23|
Quarterbacks have a decent amount of control in their pressure rate, but we were surprised at just how low the correlation is (0.05) for defensive pressure rate. A scheme change from a blitz-happy system to better coverage can certainly have an impact, but that's still amazingly low. Every defense that ranked in the top 10 in pressure rate in 2012 ranked 11th or lower in 2013. In previous years, the top 10 retained two (2012) and five teams (2011).
The DVOA success with pressure is close on both sides of the ball, which bodes well for my theory of pressure leading to a chaotic game with random results. Take pressure away and defensive performance is higher correlated, but a whole unit still can't match the consistency of one quarterback throwing from a clean pocket.
Maybe the oddest result is that pressure drop had a small, but still much higher correlation (0.14) for defense than it did for the quarterbacks. It's probably a good time to again note that our sample size is four seasons, and that's not quite adequate enough to draw sweeping conclusions from just yet. I took a random split of the pressure drop data and got a correlation of 0.24 for one group and 0.03 for the other. It's going to take some time before we're able to reach more confident conclusions, but that's interesting if a defense performs more consistently than offense relative to pressure. You would think the performance of 11 players (plus key substitutes such as a nickel cornerback or pass-rush specialist) would create more noise than one quarterback who knows the play design, but then again, it's not just the quarterback on offense. It's his receivers and line that also impact the DVOA numbers.
We finished our quarterback study with the Super Bowl teams, and we'll do the same here because it was such an interesting pressure matchup on paper. The only two teams the 2013 Broncos never beat were Indianapolis and Seattle. Both ranked in the top four in pressure rate. The Colts put Peyton Manning under duress on 17 dropbacks, his highest total in four years. Edge pressure defined that success with Robert Mathis forcing a safety on a strip-sack and Manning was hit as he threw on a fourth-quarter interception. That same exact "hit in motion" pick thwarted a Denver rally in a loss to San Diego, and of course the Seahawks hit the "Rout" button in Super Bowl XLVIII with a pick-six after Cliff Avril hit Manning. While left tackle Ryan Clady was certainly missed, these problems for Denver were from the right side. I'm not sure who popularized the left tackle as the only "franchise" position on the line, but right tackles are important too.
Pressure defined the season of Super Bowl champion Seattle. We know the offense had the highest pressure rate allowed in four years, but the vaunted defense also had the highest pressure rate (34.2 percent) since 2010. Cue the chicken-or-the-egg argument about their coverage and their pass rush. For what it's worth, the 2012 Seahawks ranked second in DVOA without pressure (7.7%). They can cover, but last year they brought the heat better than anyone and did so with a below-average amount of blitzing. Now everyone will want to steal that "blueprint," but it's hard to copy without the same talent on the field.
It's also apparently really difficult to keep getting pressure each season, so enjoy it while it lasts. Carpe diem, boys.
38 comments, Last at 23 Sep 2014, 2:22pm by