Defense By the Numbers

Here’s a quick recap of every current news story in the NFL:

• The lockout is still on.
• The players are finding a lot of different ways to pass the time.  Sometimes they get together to exercise, and sometimes they hit the town and skip out on their bar tabs.
• Sportswriters are coping by writing hundreds of gimmicky list articles.  (I keep hoping that the editors at NFL.com will get fed up and break Adam Rank’s fingers, but alas.)
• The owners and NFLPA are deep in negotiations concerning whether or not they should have another day of negotiations.  If they do, I expect it’ll only be because they didn’t have enough time the first day to finish arguing about whether or not they should continue arguing.

Welcome, ladies and gentlemen, to the offseason doldrums.  I remember reading somewhere that when they put military personnel through torture resistance training, one of the techniques they teach them is to shut out the torture by focusing on a different pain somewhere else in the body.  For example, if someone is repeatedly kicking you in the gonads to get you to give up state secrets, punching yourself in the arm can help you better ignore both your captors’ questions and the beating they’ve so generously applied to your beans and franks.  In much the same spirit, I thought I’d help you guys shut out the searing tedium of the CBA talks by talking for a bit about the 2010 Seahawks’ defense.  You’re welcome.

To get a read on how the defense performed last year, I figured the best way to go was to delve into some statistics.  More specifically, I took the season averages for each offense the Seahawks faced in 2010 and compared those stats to the numbers they put up against Seattle, the idea being that if an offense put up lower stats than their seasonal average then the Seahawks’ defenders probably did an okay job in that game.  Conversely, if an offense managed higher than average stats, then the defense probably didn’t do so well.  Simplistic, I know, but given the team’s struggles the last few years I don’t think that looking at whether or not the defense performed at least better than average in a given game is setting the bar too low here.

Let’s start with a general overview of the defense’s effectiveness:

Blech.  The Seahawks were able to hold an opposing offense to a lower than average score just six times last season -- five, if you don’t count that paltry -0.1 point difference in the second game against the Cardinals -- and in terms of total yardage allowed the defense did better than average on just four occasions.  Those totals look even worse when you consider that most of those above-average performances were against weak divisional opponents.  Outside the NFC West, the Seahawks only kept the score down twice and the yardage down once.

In short, the defense was officially Not Good, but we already knew that.  To learn more about what exactly went wrong, we need to break the stats down further to see how Seattle did against the run and the pass individually.  First up, here’s how the run defense fared:

While still not great, at least there’s a little more eye-soothing green to be seen on this table.  As you can see, the Seahawks started off the year respectably enough against the run, then trailed off through the middle of the season before getting their groove back in three of their last four games.  Also, the games against the Raiders and Buccaneers look just as ugly on a spreadsheet as they did on television, but that’s another subject altogether.

So then, what the hell happened?  The first possibility is that it might have simply taken until game six or so for offensive coordinators to zero in on how best to attack Pete Carroll and Gus Bradley’s 4-3 Leo front and then taken until game thirteen for the Seahawks’ coaches to effectively neutralize those counter-strategies.  However, unless someone has the time, interest, and (more importantly) access to game film to determine how much the offenses in question altered their run game strategy when they faced the Seahawks, that potential answer is going to have to remain unexplored.

A second thing to consider here is whether the answer might simply be strength of competition.  If that were the case, then I’d expect the defense to spend the season performing reasonably well against bad teams and wilting against good teams, but that doesn’t seem to fit the pattern here.  Yes, the Seahawks were trounced by three top-ten rushing teams during their mid-season slump (the Chiefs, Raiders, and Giants), but in that same stretch of games they also didn’t do so hot against the 28th-ranked Saints or 32nd-ranked Cardinals, either.  Also, two good showings against the 25th-ranked Rams at the beginning and end of the year certainly help make the run defense look a bit better, but also included in those first and last few games are performances against the 12th-ranked Falcons and 15th-ranked Chargers in which they held both teams to zero touchdowns and lower than usual yardage numbers.

Thirdly, we have the popular opinion folks have been voicing both in print and online, namely that the reason for the run defense’s drop-off is all the injuries the team suffered along the defensive line, the most notable of which being the knee injury that ended Red Bryant’s season partway through the game against the Raiders.  And as it turns out, this appears to be one of those rare occasions when the anecdotal evidence and the actual evidence agree:

As you can see, there’s a strong correlation here between the stoutness of the run defense and the health of the opening-day starters on the defensive line.  However, the player who had the biggest impact does not appear to be Red Bryant, who can hardly be credited for the defense’s return to adequacy late in the season since he was on injured reserve.  Brandon Mebane missed games five through eight, but his return in game nine against the Cardinals doesn’t seem to have increased the team’s ability to stop the run, and Chris Clemons never missed a game so he isn’t the answer here either.  Interestingly enough, the key loss to Seattle’s run defense appears to have been the least-hyped member of the d-line, Colin Cole.  It’s true that things began to fall apart after Bryant was injured against the Raiders, but Cole was also injured in that game, and his return to the starting lineup in game thirteen just so happens to coincide with the first of three strong showings to end the season.  Patrick Kerney’s one monster year aside, Colin Cole may very well be the best free agent pickup of the Tim Ruskell era.

So then, the run defense appears to have been doing at least an adequate job (for half the season, at least).  That must mean we can blame the pass defense for the defenses’ terrible overall stats, right?  Right:

This article is already getting a bit long, so I'll cut this last part short.  Suffice to say that stats as bad as these pretty much speak for themselves, and that the Seahawks' secondary doesn't have the same injury excuse as the d-line (Kelly Jennings was the only starter in the defensive backfield to miss some starts, and he isn't exactly an irreplaceable talent).  Is it any wonder that John Schneider took three defensive backs in the draft this year?