The Seattle Seahawks will be using a predominantly zone blocking scheme when running the ball in 2009. Firstly, let’s look at an example run play and some of the duties expected from the offensive line.
Offensive line: LT, LG, C, RG, RT, TE
4-3 defense: DE, NT, UT, DE / Will, Mike, Sam
For this example the play call is a run to the right. The center and right guard will block the UT and the right tackle and tight end will block the strong side defensive end.
When the ball is snapped the two defensive tackles are being double teamed which should move them backwards. The focus on this initial push through the middle could bring the linebackers into play. On a run to the right the Will LB is unlikely to have much impact unless the running back breaks into the second level.
The center and right guard would have to read the Mike LB together and decide who is going to break off up field and who stays with the UT. It's fair to assume the Mike will make the correct read and stretch outside making the guard the most likely option to cover.
He would need to perform a scoop block, a speciality of the zone blocking scheme that values athleticism over big heavies.
The Sam linebacker will shoot outside forcing the tight end to take him. If the defense has sufficient safety support, he could plug the inside gap.
If the play was changed at the line to run up the gut instead, the left guard and center would block the NT with the right guard and right tackle taking the UT.
As with most examples, it’s dependant on personnel. In this situation the tight end may need help blocking the edge as even a first class blocking TE would struggle against Julius Peppers.
Running through the middle, both DT’s are again double teamed but less attention is paid to the defensive ends. This could bring the linebackers into play so a good seal block on the Mike would be needed to potentially wall off the Will and Sam.
In both situations the running back will be expected to find the hole that develops, make one cut and break into the secondary. The zone blocking scheme in general is less restrictive to backs and allows them to play with greater instinct, allowing blocks to develop.
There are different variations of the zone blocking scheme though, so what can we expect to see in Seattle?
New offensive coordinator Greg Knapp is more a proponent of the type of system seen in Denver over recent years. This places greater emphasis on smaller offensive lineman with superior athleticism, with a lot more cut blocking. The center is often key because the guards don’t have the size to move opponents on their own.
Offensive line coach Mike Solari has predominantly favoured a slightly different variation. It could be described as a "power ZBS" in that the guards are usually bigger and do most of the heavy work load.
Unlike Knapp’s ZBS, they are the primary movers with the center more likely to progress to the second level and attack linebackers due to directional drive blocking.
The advantage of Solari’s system is that if a defense goes run blitz, the linebackers can be driven out of the play creating huge gaps.
It's possible the Seahawks could combine the two. Looking at the current roster, the potential is certainly there to be flexible.
Guards Mike Wahle and Rob Sims are athletic enough to fill Knapp's ZBS. Wahle in particular has good technique and should be able to execute well as a starting left guard. Neither are the big power types that would usually be used in Solari’s scheme.
Mansfield Wrotto, however, stands at 320lbs—the perfect kind of weight to fit the power ZBS. He's also a good athlete, so he could excel in this system. The downside is he’s still a little raw even approaching his third year in the league. The mental side of the Solari version is less demanding which could help Wrotto get on the field.
The center position is a point of contention. Chris Spencer has the freaky athleticism and solid strength which would make a good fit at guard in either system. His issue has always been execution and technique, which would be a problem at center in either scenario.
Recently drafted Max Unger is a little more predictable. He is an obvious guard in Knapp’s ZBS background and a center in Solari’s. I have to believe the Seahawks won’t be willing to flex between the two at center, but they may have to in certain circumstances.
Unger does tend to struggle with leverage which may put him at a disadvantage. Taking this into account, it wouldn't surprise me if the starting offensive line in 2009 consisted of Walter Jones (LT), Mike Wahle (LG), Chris Spencer (C), Rob Sims (RG) and Sean Locklear (RT).
Wrotto could spell at right guard in a more power driven ZBS, with Spencer and Unger possibly fitting into the line to replace Wahle in that situation.