Monday, February 7, 2011

Why Isn't Chris Clemons Helping?

Admit it, you've been wondering about this. In 2010, Chris Clemons and Raheem Brock notched twenty regular-season sacks between them and three more in the postseason, yet Seattle's overall pass defense remained flat-out abysmal. There's a disconnect there somewhere, and it's been the elephant in the room for a while now.

John Morgan of Fieldgulls broached the issue Friday in a piece that questions the value of Clemons and of the Leo position that Clemons plays. (The Leo, or stand-up defensive end, needs to be able to play from several positions and has gotten some criticism for being vulnerable against the run - offering pass defense at the expense of run defense.)

Well, for a defense already built by former GM Tim Ruskell to defend the run at the expense of allowing the pass, I normally wouldn't complain about this. What this team needs is pass rush. But despite the production from Clemons and Brock, Seattle's pass defense was ranked 27th in YPG allowed, 29th in TD's allowed (33), 31st in 20+ yard completions allowed (60), and only 25th in interceptions, as well as 29th in DVOA pass defense.

Somehow, despite Seattle's best production at defensive end since 2007, the overall pass defense isn't improving. Where does Clemons fit into that?

The article features a chart showing that Clemons got a disproportionately higher share of sacks on blitzes than any of the league's top 20 pass rushers. The comparison mostly holds up when you look at just 4-3 ends, which has the added benefit of narrowing the sample to players within Clemons' general production neighborhood:

Top 4-3 Defensive Ends
PlayerTotal SacksSacks on BlitzPercentage
John Abraham1318%
Jason Babin13323%
Charles Johnson12433%
Justin Tuck12433%
Osi Umenyiora12325%
Jared Allen11218%
Chris Clemons11764%
Robert Mathis11327%
James Hall11327%
Trent Cole10550%
Dwight Freeney10220%
Carlos Dunlap10220%
Raheem Brock9127%

The data could imply that Clemons is an overrated pass rusher who's merely benefiting from Seattle blitzing. Blitzing can force offensive lines to shift assignments, double up on gaps, and improvise, helping free up other defenders for one-on-one matchups that are more easily won. The lower percentages for most other pass rushers suggest that they're sacking more on their own tools and merit, whereas Clemons is dependent on the blitz. But is blitzing, with its inherent risk of lesser coverage, an acceptable tradeoff to enable a defensive end?

Part of me wants to say that I don't have a problem with this, as long as somebody gets to the QB. Sacks are usually a product of the entire defense anyway. It's not as if Seattle is over-blitzing or anything to help Clemons; according to Mike Sando, the Seahawks blitzed 33.9% of the time in 2010, just a hair over the league average of 33.3%. Additionally, Seattle got a big chunk of its sacks, 35%, from its blitzers themselves. That's a high number, but not out of line with a few other 4-3 teams with good sack performance and decent pass defenses:

Sacks from Blitzers (LB's and DB's)
Team% from Blitzers
Philadelphia Eagles38%
Oakland Raiders37%
Seattle Seahawks35%
St. Louis Rams28%
Chicago Bears26%
Tennessee Titans19%
New York Giants12%
Detroit Lions9%

But this doesn't confirm the value of Clemons or make the pass defense any better. I think two questions are begged here.

1. How valuable are sacks as a measure of a defensive end's play?

Sacks by themselves are a deceiving statistic. Some are coverage sacks, created by good coverage downfield that buys the pass rusher more time. Others are just worthless, such as pressure from one pass rusher sending the QB into the arms of another who wasn't factoring otherwise, crediting the right guy for the sack but the wrong guy for the play's success. It's possible to record several such sacks without ever having an influence on a QB's play (see: most of Lawrence Jackson's resume in Seattle).

And not every effective rush even results in a sack. Other results of pressuring a QB might be to force a check down, early throw, throwaway, or scramble - "QB hurries". Defensive ends also need to be able to take down running backs behind the line and, in a Tampa 2 scheme like Seattle's, even drop into coverage. In that sense, sacks are only part of a defensive end's worth, and ignoring those domains in favor of sacks alone will give an incomplete picture.

On the flipside, however, show me a defense that succeeds without sacks. Maybe some of us do over-fixate on sacks, but there's a lot to be said for actually putting a QB on the ground. A scramble, check down, or incompletion may be a success for a defense because of the reduced gain, but the offense hasn't gone backwards. An interception from a QB hurry is a very worthwhile gamble, but still a gamble, especially from a quality QB. A sack, however, creates instant and tangible loss of yardage for an offense. A throwaway on 2nd and 5 just produces a manageable 3rd and 5; a sack can give you 3rd and 15, shifting the play call, forcing adjustments, and making another blitz likelier to get home.

This is where theory and results collide. One defining attribute of an elite QB is pocket presence, the ability to make plays in the very face of pressure. You hear people praise QB's for "staying cool in the pocket" (or not) all the time, perhaps calling into question the value of QB pressures. The picture at the right depicts Brees shrugging off a pressure before converting a 2nd-and-9.

That's just one of countless examples I can show you. Seattle has been victimized by so many last-second, three-inches-from-the-sack completions from elite QB's in the last two years. The Seahawks themselves have reached the playoffs on the back of such plays by Matt Hasselbeck (0:57 and 1:21 mark). Yes, the impact of plays like this is harder to quantify or predict - yet they happen every week and change the outcome of games.

So sacks by themselves don't define a player, but pressures by themselves don't define a game. The sacks have to come from somewhere, and in the 4-3, the DE is the primary supplier.

2. What is Clemons Himself Doing?

If it's empty sacks you're worried about, Clemons also ranked 10th in the league in QB hurries per game through Week 14, with 2.0 per game. Those are in addition to sacks, and also don't include the parade of un-called holds that Clemons put up with allll seeeeason loooong. So Clemons has a volume of work besides just sacks, making it easier to justify his value against the risk of blitzing.

(Interesting note from the hurries chart: Chris Long and Mario Williams, the league leaders in 4-3 hurries, converted markedly fewer hurries into sacks than most of the others - and both play on bad pass defenses. Curious, but I'm not making conjectures yet.)

Now to quickly glance at each of Clemons' sacks on blitzes:

1. vs. San Diego, 5:08 in the 3rd: Seattle blitzes all right, loading the line and sending six. The blitz leads to one-on-ones, but Clemons just beats LT Brandyn Dombrowski with a good burst off the snap, nailing Philip Rivers on a deep dropback.

2. @ St. Louis, 1:10 in the 4th: Lawyer Milloy blitzes from the left, but Clemons on the right just isn't accounted for by the line. Gimme sack, but every DE enjoys those now and then.

3. @ St. Louis, 6:58 in the 3rd: Seahawks send five, Junior Siavii flushes Sam Bradford out and chases him toward the right sideline. Clemons, who cut inside through the scrum, stays in the play and runs Bradford out of bounds just behind the LOS, registering a sack by getting a hand on him.

4. @ Chicago, 5:47 in the 4th: Jordan Babineaux comes unblocked off right and applies most of the sack. LT Frank Omiyale looks torn for a split second between Clemons and Roy Lewis blitzing off left, and that's all Clemons needs to push past him; LG Chris Williams doesn't help, as he peels off to block Lewis.

5. vs. Arizona, 14:13 in the 3rd: Another perfectly timed snap and Clemons schools LT Levi Brown around the edge (Brown had a bad year with Clemons). Roy Lewis' blitz off the other side sends Derek Anderson scrambling forward, which actually made it a little harder for Clemons, but he gets the sack.

6. vs. Carolina, 5:10 in the 3rd: Jimmy Clausen gets spooked and scrambles, I think, a little too early. Clemons disengages to track him down after having been neutralized by LT Jordan Gross.

7. @ San Francisco, 12:32 in the 2nd: Aaron Curry wraps up Alex Smith and helps Clemons get in on the action, but yet another good first step by Clemons.

8. @ Tampa Bay, 1:04 in the 1st: Clemons stunts inside and blows through the left guard, helped by great push from Brandon Mebane and Jay Richardson. Curry was blitzing off right, but on a late walk-up blitz that got picked up by RB Cadillac Williams.

Conclusions: On most of these plays, Seattle is freely showing blitzes well before the snap, with Clemons mostly coming from offensive left. It's possible the blitz looks could be helping Clemons achieve one-on-one matchups by convincing offenses to adjust. But otherwise, the blitzes don't seem to be directly impacting Clemons' duties. Clemons, for his part, is using a terrific first step to out-race left tackles and has good closing speed to finish the job. They're certainly not all cheapie sacks. Astute fans might also remember some impressive inside moves from the preseason, with which he beat Pro Bowl left tackles like Bryant McKinnie and Michael Roos.

So, Seattle is getting production from Clemons and is still able to apply effective pressure from elsewhere on its blitzes. That pressure is largely from the hot-and-cold Bandit package, but that's another argument. Also another argument is why Seattle's pass defense is truly struggling, because there are all kinds of other possible culprits. The interior D-line picked up exactly two sacks this year, which is just plain bad. The back seven, especially our nickel personnel, just don't cover very well. Defensive coordinator Gus Bradley doesn't seem to have a natural feel for timing his blitzes yet. Not only would those factors help explain the situation, but they've been plainly obvious all season. Plenty of blame to go around.

The data, combined with my opinion toward the value of sacks, has me leaning towards the belief Clemons is not the problem, neither counterproductive nor irrelevant. He's just can't overcome the collective struggles of this defense, and shouldn't be expected to. Nobody ever (reasonably) said he was elite, but he's a solid, toolsy pass rusher who's doing his job. This is neither definitive nor broken down nearly as deep as it could be, but he brings sacks, and if you aren't the type to believe in the value of actually bringing the quarterback down, talk to David Tyree:


  1. I think it all boils down to cornerback play. They just arent getting the job done.

  2. True enough, although I actually want to do a boil-down of Trufant's performance. I think his contributions have been a little under-rated.

  3. Mebane, Cole, Bryant, and Balmer soaked up the majority of snaps for every spot on the line other than the LEO position. Those four players combined a grand total of 3 sacks in 2010.

    For a cover 2 defense to work, you can't sacrifice pass rush from any position in the front four, and Seattle was basically only getting its pass rush from the LEO and creative blitzing.

    If Seattle wants to fix its defense with the same scheme, then upgrading the nose tackle and the 3 tech has to be at the top of the list. Brandon Mebane is a great run stuffer but not a great 3, and Cole is a decent 2 gap commander but provides zero pressure.

  4. One comment Morgan made is that Seattle appears to have placed most of the team's responsibility for pass rush on Clemons. I wonder whether this move was deliberate, since the other DE position doesn't appear intended to create pass rush, or more of a concession in that PC would like more rush from others but doesn't have much at the interior.