The X’s and O’s of the Desai Defense – Part 1

Image by Zachary Rosenbaum –

Surely you’ve watched a football game before, and the commentator bellows out, “They’re bringing down a safety and making an eight-man box to stop the run!”. This may have been traditionally when safeties themselves were defined as a bigger linebacker like, “strong safety” like say a Troy Polamalu, while “rangy” free safety like say an Ed Reed would hang back and make plays. That traditional in the box attacking safety is still around in the form of Jamal Adams, however, safeties have been much more interchangeable this decade, but they hold the same value for the defense, and are the secret code to crack for the offense.

Traditionally, most teams play both of their safeties up high. As spread football has flourished across the collegiate ranks and seeped into the NFL, an extra defensive back has usually come onto the field in place of a linebacker, or linemen. How safeties are used depends if a team runs a three or four front, and in reality, most teams design their defenses from the front to the back end. If this is the case, and safeties are sort of considered the “filler” when it comes to roster building, (as opposed to cornerbacks, edge rushers, etc.) What makes them so valuable? It’s not who they are, it’s how they are utilized. Here me out on this one.

Let’s play a simple math game. Every defensive box player near the line scrimmage has a gap they are responsible for in the run game. So between each offensive lineman and outside of them equals 8 gaps if there are two tight ends, or 6 gaps if you remove the tight ends.

Look at the lettering below. These are the gaps for both the offensive and defensive lines. Each defensive lineman or linebacker are responsible for occupying these gaps. To distinguish between them since they are in multiples of 2, they are usually referred to as front side vs backside, or play side vs. weak side, etc. For example, regardless if in an inside zone running play is going right or left, the running backs aiming point would be the front side A gap. The defensive line will line up in shades or techniques, as well will see in the next picture.

Most commonly, you see four defensive linemen and two linebackers, and everyone else out covering receivers, especially if you are watching college ball. If there is one high safety, odds are that 7th defensive player is probably relatively close to the tackle box, which can mean everyone has one on one coverage depending on the call.

Let’s use the picture down below to get more in depth. The four D linemen are in their various shades or techniques depending on the call or the front. As long as the gaps they leave open are taken by the linebackers, the puzzle will fit together. (Even though it looks like 54 is doubling up the B gap with the D tackle, they may have a call on where one of the two fills that open A gap post snap).

 If you notice #23, he isn’t quite in the box, but he’s close. This is likely because there are two backs in the backfield, insinuating a run call. He needs to be close enough to the box for the run, but have time to get to his work in coverage if it’s a pass.

Not seen in the picture, are the three other defensive players, likely responsible for the three receivers outside of the frame. That leaves no 32 as the single high safety. That single high safety can easily tip off the QB and opposing coaches of the coverage (likely Cover 3, or Man free), and there are certain route combos that kill that coverage, just like the coverage works well against certain route combos. Again, it’s like a giant puzzle piece. (A lot of big plays either positive or negative that you see on Saturday or Sunday sometime come down to either coordinator just guessing right, or catching the other team in the wrong play.)

Defenses can counteract downfield attacks with two high safeties, creating almost an umbrella across the top of the defense. With our focus still on the Patriots diagram, let’s say #23 Chung moved up to a high safety spot to join #32. Now you might say, well great, one less guy near the tackle box, as well as an available gap, if I’m on offense, I’m going to run the ball!

Totally fair point. BUT, depending on how good your D line is, you can have one D lineman be responsible for two gaps, now it’s almost like you have a 12th defender on the field. With that extra gap filled, every defender’s responsibility can be bumped down one gap, which would send that extra overhang defender OUT of the Box, and up high, helping to create an umbrella.

This is where Sean Desai as part of the Vic Fangio tree is going to make his money. This 3-4 front is becoming more popular even in college, and a perennial playoff team that has joined my high schools conference runs this, too. It forces you to change blocking schemes with kickouts and double teams, the whole nine yards. Most teams like to run Power with a pulling guard into those B gaps. It’s Okay to have the nose take two gaps, especially if he is a Vince Wilfork sized monster, or even say an Eddie Goldman of the Bears, because teams don’t hit that A gap as hard as they might the B, C, or D. It helps having the right personnel, like a hulking Defensive Tackle like Akiem Hicks to make things work. As for the outer shell, of the defense, the main focus is avoiding the big plays. Next week we will focus on this two deep shell scheme that is being used to counteract the influx of Inside zone/play action offenses made popular again by Kyle Shanahan and Sean McVay.

Hint: I bet Kyle’s dad ran the same stuff with 1990s Broncos. See you soon.

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