Defending the I Formation like Pete Carroll’s Seahawks Defense


The Seattle Seahawks dominated many I formation teams this year. Under Pete Carroll, the Seahawks defense had a nice little adjustment to pro style formations, like the I formation.

Especially in 21 personnel, 2 backs and 1 tight end, the Seahawks defense matched up well. One way they did that was playing a “heavy” end on the weakside.

Many defenses declare passing strengths instead of declaring it to a tight end and then they set the shade side, or open side, to either the tight end or the split end.

seahawks defense vs pro formation

How Many Teams Play the Over Front vs 21 personnel

The Seahawks do it a little differently. While the Seahawks defense in 2013 set the reduction, or 3 technique side, to the tight end in many situations. The nose and Sam linebacker get set to the split end. The strong safety, who I call the Rover, is set to the 3 technique side.

Eliminating the Over Front’s Weaknesses to Split End Runs

Seahawks defense against the Colts

Notice how the safety is up near the TE and the 4i on the split end side

The end to the open/nose tackle side usually plays a 5 technique, with the Sam linebacker playing in a 40i technique. In the Seahawks defense, they played a 4i or 4 technique with their end to that side. He was a B gap player (though he does 2 gap a lot, as Chris at Smart Football explains here) and late container on the rush in many situations. The Sam linebacker played up near the line of scrimmage. He was responsible for the curl/flat in cover 3 still, but he was C gap versus the run.
Seahawks Defense vs Pro

Seahawks Look

This heavily discouraged teams from running to that side. It’s hard to dig the 4i or even 4 technique out of the B gap, with his heavy presence. So Isolation plays, typically ran to this side against over fronts, are eliminated.

Toss plays are tough as well, thanks to the 4i and Nose protecting the Mike linebacker and the wide Sam linebacker. It is also hard to get the edge on the Sam linebacker with such a heavy player across from the offensive tackle in the defensive end.
Seahawks Defense Run Fits vs Toss Sweep
Power-O to the split side is tough too against this look unless you can win the 3 frontside matchups (Tackle on the “Heavy” end, Guard on the Nose, and Center on the tight end side 3 Technique).

Defending Tight End Side Runs

This defense is still strong against tight end side runs. Remember, since weakside runs are basically eliminated, the defense can play faster to the strong side. Also, since the Seahawks defense plays cover 3, the strong safety/Rover – Chancellor – is able to come down. He is basically an athletic linebacker.

The Seahawks defense will sometimes play the Rover about 3-4 yards off the line of scrimmage. Regardless, with the 3 technique and the 6 or 7 technique end, the play will likely get bounced outside to Chancellor. The two remaining inside linebackers, the Mike and Will, can fill inside/out on offensive tackle runs.

In all honesty, the best runs are A gap runs to the strong side. However, this can be thwarted too. Many teams will tilt the nose, like the Seahawks did in the images in this article. This way they can condense the A gap. The 3 technique can penetrate or hold his own, but regardless the nose is essentially two gapping from an angle, even if he’s just responsible for the split end side A gap. By forcing the center to the playside using basically a bull-rush technique, the playside A gap gets squeezed. The tailback feels like the play needs to bounce or cutback. If it cuts back, the Sam linebacker is there. If it bounces, the Rover and linebackers are protected.

One problem can be Power-O to the tight end side. The Seahawks will cheat their linebackers that way a bit because of all the protection against Power-O teams. That’s likely because there are two people in one gap vs tight end side power, specifically in the guards former gap. Both the nose and that 4i end are there. This makes it important for the linebackers to over pursue on Power-O. Again, the scheme helps here. There is minimal cutback on Power-O, which while rare, can happen. Also, the Sam linebacker is likely unblocked and can force the play to bounce, again another reason why the linebackers can over pursue.

Overall Strengths Defending Pro Formations w/the Seahawks Defense

Because of their dominant corners that could press while playing the deep outside third, the Seahawks defense took away the quick passing game. Because of their alignment and heavy looks in the running game, the Seahawks defense took away the split end side runs. Because of their over hangs (Rover and Sam linebacker), there is a nasty possibility of your QB getting killed on a play action pass. Also, the Free Safety eliminates the post route.

Seahawks Defense vs the 49ers Offense

Another look at their defense vs a 21 Pro Pistol Look

It’s a strong adjustment when attacking 21 personnel, especially 2×1 pro sets. It also easily adjusts to 22 personnel (4i in the B gap, Sam C gap when the 2nd tight end is to the weakside). However, 2 fast receivers to the split end side can cause problems, such as 2×1 slot sets to 2×2 sets. We’ll discuss adjusting to that next

Adjusting to Spread and Slot Formations

Handle 2 fast receivers to one side is easy. The 4i becomes the 5 technique again and the Sam linebacker does his coverage rule.

Seahawks Defense vs 21 pro backfield motion

Adjusting to Backfield Motion

This works really well out of the backfield regarding motion.

If the flanker, or Z receiver, comes across creating a twins look, this is different. A team can now exploit the B gap bubble. One way to handle this is to have go corners over. The corner goes across and you adjust the coverage in some way. If you don’t want to go corners over and don’t want to lose the B gap threat, you could play 2 read or cover 2. Essentially you create a hard flat player out of the corner if #2 goes flat.

Seahawks Defense vs Motion

Checking to 2 Read or Cover 2 and Going Corners Over is a Good Adjustment to Slot Sets

Note, when the offense starts in the slot look, the defense might be differently aligned. That’s because they call their strength to the other side in many of these situations.

Applying the Scheme on Your Team

I’m all about recycling technique. If you play a 6 technique or 7 technique, your ends will be used to playing inside or at least having a “C” gap presence. The technique will be the same for your split end side defensive end.

Also, you can use the element of surprise. Pick and choose when you use this scheme. Or save it for when you’re getting beat on the split end side.

Regardless, it does take some talent to run this every play. You essentially need two stout ends and one strong defensive tackle in the least. This can be hard to come by. However, in running situations you could put in 4 defensive tackles instead and use them like this. While the two replacements might not be the best defensive tackles, the offensive players will likely not be used to the heavier technique ends, giving your players an advantage.

So while there is a lot of scheme, don’t forget the matchups. Don’t put a light end in a 4i technique on a stout offensive tackle.