The 4-3 Under

As requested by bigblue777, a quick look at the 4-3 Under defensive front.

"The scheme with 4 down linemen is simpler because they will always be down. They don’t have to learn to cover the pass." Monte Kiffen

Monte Kiffen is given a lot of credit for pioneering this defense during his time at Nebraska. Coaches who have worked under Kiffen tend to prefer this defense as their base. The prime example is Pete Carroll, who ran it at USC and will increase the snaps played in Under for the Seahawks.

"When you put a defensive lineman in a gap and tell him he has to control the gap he can play very aggressively. He can aggressively attack the line of scrimmage and not just read and react.

The more the attacking oriented the defense is the better off it will be." Pete Caroll

The basic idea is to turn the 4 man front into a 5 man front while still covering the guards. The Sam walks up, plays on or outside the TE, and the whole line bumps down a gap. Here’s a few variations of Cover 1 with a Sam blitz, a very popular coverage in Under.





You can see how it's beneficial to swap gap and coverage responsibilities to make everyone’s jobs easier. If the Mike needs to cover the Y, then he can make a pre-snap call to the End and they will switch gap responsibilities. One major variation here is the "Flex" or safety swap. This gets that 8th man in the box in a different way. The Under is pretty solid to the TE side with dedicated players in the C and A gap, as well as the Sam outside. On the weak side, the Free can creep up to cover a slot or even come off the edge.

You can play a bunch of coverage variations and blitzes out of this front; the following slides are just a few examples.





The first two diagrams are just cover 3 and cover 2 man. No real differences here, just putting a bit of pressure on the Sam to hustle to his zone or really stick with the Y. The second two are some blitzes you can easily run. You can play Cov 1 and rush 6 if one or both of your extra rushers keeps an eye on the back.

The bottom diagram is a crazy play, some call it cloud, pack, or just 2-Open because you’re playing Cov 2 to the split-end or open side. You could also call this to the field, just play Cov 2 to the wide side. You get man on the strong side, and cover 2 rules opposite. The key is the Mike, who is basically going to have play zone if the back stays in to protect, with an eye on the Y if he beats Sam to the inside and looking for anything coming in from the Cov 2 side. You would only play this if you were worried about the 2-reciever side and had a rangy Mike, and you would call it very rarely. These are gameplan plays where you see a situation you can play a risky coverage and pressure to once in a while.

Here’s a summary:

Under Front

· Advantages:

o Presents a five-man front, great against run

o Confuses blocking schemes- "For strong rushing teams that base out of I-backs, we like to get another man on the front line…this reduces some of the blocking angles on our linebackers and establishes a stronger LOS that has fewer inside seems." –Bob Stoops

o Protects the Will and Mike from blockers, allows them to play in space

· Weaknesses"

o The Sam needs to be excellent (Cushing for the Texans played it well)

o The Sam is on the line, so if he has pass coverage responsibilities you are vulnerable to Play Action

o Requires a lot of checks because you don’t want to play it against Spread, Empty, or several other sets

o Not a great formation to run complex coverage out of because you are dedicating one of your back 7 to the LOS

Those are my basic thoughts on it. How about yours?

Do you like this front for your team? Do you think they have the personnel- who would play where?

If you could get a guy to play in this front in the upcoming draft, would you want to see more alignments like this?

What particular advantages and disadvantages do you think this front has against the offenses in the NFC East?

(Bob Stoops quote from his article "Pressuring with a Multiple 4-3" from Defensive Football Strategies.)

Thanks for reading. Like I said last time, please let me know if you have something you’d like to see broken down- all this is useful to me to brush up and I keep it for teaching tools. I might do one on zone blocking schemes next because d-jackfan10 at BGN had a good point on the Eagles’ new O-Line coach Howard Mudd.

FanPosts are written by community members. This is simply a way for community members to express opinions too long to be contained in a comment.

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