Keying the H-back Versus Y-off or “I” Formations

One simple coverage tweak can add numbers into the box and free up your LBs versus Y-off offenses.

I learned about using a “key” read on an offset TE (H-back) in 2017 when I heard Don Brown speak at the Lone Star Clinic in College Station. In his words, he stated, that without City Check (Cover 1 with keying safeties), he didn’t know where he’d be as a coach. Those are powerful words from one of the best defensive coordinators in college football. Sometimes you need an extra fitter on the H-back, especially as more Spread teams base out of 11/20 personnel sets (Y-off), and this was exactly what I was looking for.

Don Brown’s City Check or “Key/Fox,” as Dave Aranda (LSU)/Todd Orlando (Texas) refer to it, is a Cover 1 adjustment to any two-back formation, and can also be used if the H-back turns into a traditional TE on the line of scrimmage. Both safeties are aligned 8-10 yards deep at the edge of the box and are keying the FB or offset TE depending on personnel grouping. This is a great way to give a two-high look pre-snap (Quarters), then add numbers post-snap (gapped-out single-high). Below is a diagram of Michigan running the scheme versus a 21p “I” Twin formations.

01 Key vs 21p

Both safeties are slightly tilted in and focusing their eyes on the FB. Whichever way the FB inserts or moves, the safety to that side will trigger down to “cap” the box fit. Most defensive coaches want plus numbers in the box. The term cap refers to the third man responsible in the fit. There should be an inside and outside shoulder player on the ball carrier. The “capper,” or third fitter, caps or tops the fit.

Inside the box, the LBs are focused on the RB, and if the back were to go out for a pass (more likely versus a Shotgun offense), the LB to the RB’s side would take him. The rest of the secondary is locked on their man. In terms of pass coverage, the safety away from the inserting FB will work “through the Post,” creating a Cover 1 look. Below is a clip of the play illustrated above, a simple Iso from 21 pers. I Twin.

The motion by the Badgers’ FB triggers the safety to the nub-TE’s side to start working down. Wisconsin is used to seeing City Check from Michigan and understands how to manipulate the trigger. The open “A” gap is actually away from the motion, and the FB works back to it on the snap of the ball. Inside the box, the LBs must understand the leverage of the secondary and how the FB’s movement will trigger one of them. In the clip above, the ILB hits the FB away from the dropping safety (referred to as “boxing” the block), essentially forcing the ball carrier to the safety. The overall result is a short gain. Continue reading “Keying the H-back Versus Y-off or “I” Formations”