Eight weeks ago, the Vikings were undefeated and ranked No. 1 in DVOA. Now they're 6-6 and probably done. What went wrong?
24 Jul 2012
by Danny Tuccitto
With training camps about to start, the 2012 season is just around the corner, so it's time to finish up our series of posts detailing noteworthy charting stats from 2011. This week's topic: pass pressure. We'll start with defenses, and look at quarterbacks in a few days. These and all the other stats we've discussed this offseason appear in the statistical appendix of Football Outsiders Almanac 2012, which is on sale both in print and as a PDF file.
In previous years, we made a weird error: When we talked about how teams did with pass pressure, we only looked at hurries, not scrambles. That's kind of silly, isn't it? So this year, we made sure that we marked every play as either "pressure" or "no pressure." All sacks were marked as "pressure" plays except those marked either "Coverage Sack" or "QB Fault." (QB Fault sacks are when a quarterback slips on the grass or drops the ball on his own.) We also marked a play with pressure if it was either a quarterback scramble or a pass attempt where we listed a defender with pass pressure, or we listed "overall pressure." Finally, keep in mind that the stats in the table below include yardage and DVOA from defensive pass interference penalties.
|Rk||with Pass Pressure||without Pass Pressure||Difference|
|Rk||with Pass Pressure||without Pass Pressure||Difference|
We've sorted the table by pressure percentage, so let's start the discussion there.
For the second year in a row, no defense pressured opposing quarterbacks as frequently as the Texans did. The fact that Houston repeated despite missing Mario Williams for most of the season is a testament to Wade Phillips and their pass-rushing depth: Four front-seven defenders not named Mario had at least 20 hurries and five hits on opposing quarterbacks. That, along with drafting Whitney Mercilus, should soften the blow of Williams' departure to Buffalo, where coincidentally the Bills also repeated their ranking from 2010.
Just below Buffalo is Green Bay in dead last, which might seem surprising until you remember -- it's been a while -- that the Packers defense also ranked dead last in Adjusted Sack Rate. What separated them from the Bills, however, was that the Packers better maximized their efficiency on the relatively rare pass plays in which they did get pressure. Perhaps that's one factor that explains how the 24th-ranked pass defense can go 15-1 in this day and age.
Speaking of just winning, NFL Network reran the episode of A Football Life featuring Al Davis yesterday, and showed a clip of him mentioning how his main emphasis on defense, as early as 1963, was putting pressure on the pocket. Presumably, coaching in the pass-happy AFL had something to do with it, but no doubt he was simply inferring its success from past experience. I bring this up not to name Davis as a pioneer of pressure, nor to lure Raiderjoe into the comment thread (OK, maybe there's a little of that), but simply to point out the following. If league-wide DVOA averages in the table are any indication, advanced statistics about today's NFL lend numerical support to what Davis (and others) opined 50 years ago: pocket pressure is paramount.
Of course, it's not just that the average defense was more efficient with pressure in 2011; every defense has been so for the two years we've been keeping track. Now, at this point you might be thinking, "Well, duh. Sacks are hugely positive plays for a defense, so of course a defense's DVOA with pressure is going to be awesome when sacks are included." And you'd be right. However, this phenomenon persists even if we remove sacks, intentional grounding calls (which are essentially sacks), and scrambles from the equation so as to focus solely on hurried throws. In that case, Cincinnati had the lone defense that was actually better without pressure last year (+1.4% DVOA difference), while only Jacksonville (+24.5%) and Seattle (+13.8%) bucked the trend in 2010. That's still 61 out of 64 possible teams that benefited from pressure having nothing to do with the yardage lost on sacks.
Almost all defenses are better with pass pressure than without, but the size and nature of the difference varies wildly from team to team. A handful in 2011 were like the '85 Bears (or '91 Eagles) when they got pressure, but like the '09 Lions when they didn't (e.g., Washington). This group included both Super Bowl participants, one of which was missing its best pass rusher in early February. The other happened to have their three Pro-Bowl pass rushers as healthy as they had been all season. And no, I was not contractually obligated to point that out.
Trolling aside, the member of that boom-or-bust group with the most misleading split is Minnesota. That's because the Vikings' stellar DVOA with pressure was almost entirely due to sacks, which were almost entirely due to Jared Allen. Focusing again only on throws with pressure, their DVOA inflates by 147.9 percentage points, and their ranking drops all the way from fourth to dead last. Those kinds of numbers make it almost masochistic to think about how spectacularly awful Minnesota's 32nd-ranked pass defense would have been if not for Allen narrowly missing out on Michael Strahan's NFL sack record.
On the other end of the spectrum were several defenses that got a smaller efficiency premium from pass pressure than other defenses did in 2011 (e.g., Atlanta). In this group, the Jets, 49ers, and Dolphins stand out as being the inverse of the Vikings. All three have bottom-tier DVOAs with pressure when we include sacks, intentional grounding calls, and scrambles, but ascend up the rankings when we focus only on thrown balls (e.g., Miami jumps all the way from 29th to sixth). What this trio had in common was a rusher who amassed a hurry total wildly disproportionate to his sack total. Calvin Pace had 20 hurries but only 4.5 sacks, Justin Smith had 28 hurries but only 7.5 sacks, and Cameron Wake had 39 hurries but only 8.5 sacks. On the other hand, Jared Allen actually had more sacks than hurries (21.5).
That's all for now. Stay tuned for Part 2 later this week, where stats will agree with another long-standing, pressure-related bit of NFL intuition. No Al Davis, though.
34 comments, Last at 26 Jul 2012, 6:53pm by zenbitz