Understanding zone blocking and the future of the running game: Part 1

By Kip Earlywine
I need to preface this post by admitting up front that I'm not a big expert on Zone Blocking Scheme. If anyone is reading this and wants to make corrections, please feel free to contribute in the comments.

I played offensive tackle in high school and college, but at both levels, we used the time-tested traditional "man-blocking" system. Before the Seahawks made the move to zone blocking scheme a few years ago, it was something I had only a vague understanding about. Zone blocking scheme prides itself for its simplicity and flexibility, but oddly enough I found it pretty hard to research as not many people seem to really know exactly how it works. Since obviously the immediate future of the Seahawks offense will largely rely on coaching legend Alex Gibbs perfecting the scheme in Seattle, I thought I'd research it and make a post about how the system works and what that means going forward.

To start, I'm going to explain the zone blocking system as best as I understand it (as it relates to man), and I'll work from there in follow up articles which specifically address the offensive line and running backs.

In a traditional man scheme, every called play gives each offensive lineman his own specific assignment. On non-screen passing plays, its really simple- you pass block. On running plays, the team will attempt to open a hole at a specific spot or gap, and to do so, each lineman will carry unique marching orders. It could be simply to block the guy straight ahead, or cut your man, or double team a defensive lineman, or pull block, or pretend to pass block (in the case of a draw) or charge into the 2nd level to take out a particular assigned linebacker. Its important that assignments are done correctly, because this system puts a really high value on winning individual battles. The success of a running play is disproportionately dependent on the success of a couple key assignments being "won." This is why man scheme blockers tend to be very large and powerful. Its also why Seattle was so good at running the ball with man scheme when they had Walter Jones and Steve Hutchinson, who almost always won their individual assignments.

By contrast, zone blocking scheme tends to be more improvised and unpredictable. On most plays, zone offensive linemen are simply asked to beat the player ahead of them, or if uncovered, to double team or attack a linebacker at the 2nd level. Zone blocking likes to use pulling blockers, which I'm assuming is assigned similar to man, but for the most part, its a very interpretive, reactive system.

Whereas man gives a lineman a specific order to follow for a play, zone asks a lineman to survey the situation and decide for himself which action to take. Because of this, unspoken communication, chemistry/familiarity, instincts, quick thinking and quick movement play a larger role in this system. For example, lets say you have an uncovered guard and covered tackle combination. If the defensive end crashes inside, the tackle should release the defensive end and allow the guard to pick him up, moving instead to the 2nd level to engage a linebacker. The guard has to be aware of this possibility. If the defensive end does not crash inside, the tackle picks him up and the guard must then quickly move to the 2nd level to engage a linebacker in the tackle's stead.

Its kind of amazing that such a "simple" system can regularly force offensive linemen to make split second decisions and adjustments. This is why intelligence is a highly valued commodity for Alex Gibbs type linemen. They don't just play fast, they have to think fast too.

The other trade mark of a zone system is cut blocking. A good cut block can defeat even an elite defensive lineman, but only for a second, perhaps two seconds at most. The zone scheme is built on the idea of winning at the line of scrimmage in the first couple seconds but not much longer. This is why smaller, quicker, more athletic lineman are preferred. These types tend to fire off the line quicker, which gives them a chance to engage a defensive lineman before he fully exits his stance. Even a good defensive tackle will struggle for a moment with a double team hitting him so quickly after the snap. In a lot of cases, one lineman will cut a defensive tackle, causing him to lose the use of his legs for a moment, and the other will "clean up," pushing the defensive tackle out of a gap and possibly off his feet completely. By engaging quickly and using their athleticism, a zone lineman can usually win in the early seconds of a scrum, and even if they ultimately lose, the system is designed to get the ball through the line very quickly, so that usually doesn't matter.

Another reason the cut block is used so extensively by this system is because it uses small, quick, linemen who would get absolutely demolished in a fair fight against a very big and powerful defensive tackle. Should a zone scheme center have to go mono-a-mono with Albert Haynesworth, his only prayer of victory would be to aim for his legs and try to slow him down.

The result of this system is that it creates holes and cutback lanes anywhere, and those holes tend to be fairly small and only open for brief amounts of time. As such, its of utmost importance that the runner have great vision, running instincts, burst (conspicuous acceleration), tackle breaking ability and decisiveness. The classic Gibbs RB tandem tends to be a "thunder and lightning" combination, with one runner having size and power, and the other possessing high top speed.

Justin Forsett is neither, and yet he excels in the system because he meets each of the criteria above. He has nearly Shaun Alexander level vision and instincts- but unlike Alexander he's decisive. He has terrific burst. He "plays big" and can be hard to wrap up, and as an added bonus, his tiny body often allows him to slip by defenders in the scrum. If only his tiny body did not limit his workload so much, and if only he had a top gear, he'd be a superstar for Seattle. Regardless, he's very valuable every time he touches the ball. According to football outsiders, Forsett was worth a full yard above replacement per play (including receptions- 155 combined DYAR in 155 total touches) in '09. By comparison, Chris Johnson had 454 DYAR in 429 touches, about 1.1 total yards above replacement per attempt. Obviously, Forsett benefited from being a 3rd down back, but when he was on the field, he gave the Seahawks a Chris Johnson level of contribution.

Justin Forsett isn't as valuable as Johnson because he can't manage a 450 carry/catch workload, and but get 2 more Justin Forsett caliber runners, one with a top gear and one with short yardage skills, and give the three of them a combined 450 touches, and you'd be pretty close. That, in a nutshell, is how Denver and other zone teams compiled elite rushing offenses with players who were draft day afterthoughts.

In the next post, I'll audit the Seahawks existing offensive line, and I'll name some potential options this offseason to improve the unit or make it more Gibbs appropriate. In part 3, I'll review the Seahawks backfield, and look at potential offseason options to fix the running game.