The Seahawks' gap assignments have always been a little muddled to me and I think that's because they probably purposefully change them from play to play, series to series, and situation to situation. The basic premise, as far as I understand it, is that the Seahawks ran with a mostly two-gapping from the nose tackle and 5-tech defensive end in the 2010 season, but switched to a more conventional 4-3 one-gapping scheme later in the year when injuries piled up and their defense struggled.
A one-gap scheme is what Carroll did at USC but isn't necessarily what he had planned to do or plans to do going forward in Seattle. Based on the personnel available to him, he and Dan Quinn brought in a hybrid 4-3 with principles that he had learned from former 49ers assistant coach Bill McPherson. Carroll and (former Seahawks) defensive line coach Dan Quinn implemented a two-gap defensive line scheme that was aimed at stopping the run.
The two-gap strategy used last season basically involves the nose tackle and the strongside defensive end holding the point of attack and managing two gaps in defense of the run. In the case it's a pass, the defensive linemen then try to get at the quarterback, but with any two-gap system, the moment of hesitation really hurts the pass rush. The exception here is that the LEO is only responsible for the C-gap on his side, so he's rushing the passer like a bat out of Hades.
With bigger men on the line you command more double teams from the offense and it frees up your linebackers to move in space and avoid getting hooked by the offensive linemen. With an aim at stopping the run, the idea is that you can force your opponent into down and distance that dictates a pass, then dial up blitz packages and the like to try and get to the quarterback.
As Chris Clemons described last year's defense, "When we go into the game, our first objective is to stop the run. Once we get them in that position to be in a passing situation, it's not just about blitzes, we have a lot of four-man rushes too. It's just a matter of everybody up front being on the same page and being able to get to the quarterback."
While that tactic and schema worked for a time last season, it looks like the Hawks may be looking to try something different in 2011. First of all, they re-signed Brandon Mebane but immediately designated him as the new nose tackle, a spot held down by Colin Cole last season. The NT responsibilities are going to change as well. Per Brandon Mebane, in an interview on the Kevin Calabro show:
"It's going to be, basically, like when I was here with Rocky (Bernard). Me and Rocky, we basically both played the nose and the three (-tech), you know, we slid down the line, depending on where the strength was. I played the right side, Rocky played the left side. But this year, we're not doing any sliding, it will be more like, the coach will say "I need you to play the nose this series", you know, "I need you to play the three (-tech) this series", so I'm going to basically be playing both of them."
He continued, "Probably right now for the majority of the time I'm going to be playing the nose, which I don't have a problem with, I played it before, and I'm just ready to get back out there and just have fun."
"I (will be) shading on the center. Last year, I don't know if you've seen, we played mostly a two-gap. So in two-gap, the nose (plays) head-up on the center, straight up on the center. So last year we kind of did the two-gap thing, but towards the end of the year we played one-gap.
That one-gap system is apparently what the Seahawks plan to cycle into use more often.
"I can't really say (why they're making the change). I can say that this system is effective. I think it's very effective. I actually like playing one-gap too. I mean, I can play two-gap, but you know with me being this young, I really prefer to play one-gap, you know just getting up the field, getting up into the gap, just causing havoc."
You have to think the change has something to do with the arrival of defensive line coach Todd Wash. Wash comes to Seattle via Tampa Bay, where the Buccaneers have been running a pretty traditional 4-3 defense. As John Morgan so aptly put it, "He's systems guy, pure and simple, from the wellspring, and to my knowledge free of any crazy notions about a hybrid defense. His ends are pass rushers, his tackles penetrate and his run defense is atrocious, damn it."
Morgan added, "Losing Quinn and signing Wash could mean an end to the unbalanced line. It was something Pete Carroll took on and ran with, but not something that reflects Carroll's greater coaching philosophy. In light of just how terrible Seattle's defense was, it wouldn't surprise me if some fundamental changes were made."
Predictably, Morgan's analysis seems to have some legs, as we've seen a little bit of the more traditional 4-man front in the Seahawks first preseason game with the ends manned by Jimmy Wilkerson and Raheem Brock. This could, of course, be due to Red Bryant's slow return and Chris Clemons' injury but there's a chance it could signal a move to eschew, to an extent, the hybrid unbalanced line with big Red Bryant for the use of pass rushing ends more often. It's anyone's guess at this point.
My personal take is that I don't think that the Seahawks will abandon the Red Bryant experiment. I think that with the addition of Wash, that could mean you see more 'traditional' sets where you've got two penetrating defensive tackles on the interior and two pass rushing defensive ends on the outside -- something they did with Raheem Brock and Chris Clemons later in the season last year -- but I think the Hawks will still use the unbalanced hybrid often as well.
Either way, the system Mebane refers to above where he was playing next to Rocky Bernard netted him 5.5 sacks and featured his talents and abilities to consistently get pressure on the quarterback. Whether he's one-gapping or two-gapping, history tells us he'll have a better chance to collapse the pocket and cause problems for the offense by getting into the backfield from the nose tackle position.
How they use newly signed DT Alan Branch, who will now be playing the 3-tech, in conjunction with Mebane will be something to watch closely. Junior Siavii and Colin Cole, if he gets healthy, will provide depth. The Hawks have added veteran depth at DE by signing Jimmy Wilkerson and Raheem Brock, but have also added Pep Levingston, A.J. Schable, and Pierre Allen.
They've moved Jameson Konz to the Leo to compete as depth behind Clemons and Dexter Davis (and Raheem Brock - who can play either DE spot). They'll likely move Kentwan Balmer to the interior and give him a chance to play one-gapping football, because he wasn't particularly effective two-gapping at the 5-tech last year (though he can if needed). Pierre Allen can two-gap and did so at Nebraska, but has also flashed some pass rushing ability in camp and in their first preseason game, getting a monster sack that caused a fumble. Jimmy Wilkerson can play the either DE spot but can also bump in to the interior when needed. Alan Branch is the starting 3-tech but can also play 5-tech DE (and NT in an absolute pinch). Brandon Mebane can play the NT or the 3-tech. Pep Levingston was originally thought of as a DE but has been playing on the interior a bit as well. Hell, even Aaron Curry can play as a down lineman.
My point: versatility is king on this defense. Don't even get me started on the linebackers and defensive backs.
In 2011, I would guess the Hawks will use situational packages that get different combinations of players on the field and make the defense less predictable. You could see packages with two big defensive ends and no LEO rush end, and you could see packages with two speed edge rushers going after the quarterback. The Hawks could rotate guys in and out and move players to different spots along the line or in the secondary.
It's all about down and distance, and creating confusion for the offense. It's something to watch.