How Kyle Shanahan's '21' personnel offensive sets confuse defenses

By Bobby Peters | Posted 1/4/2018

(Photo via ninersnation.com)

In a league where 11 personnel (1 running back and 1 tight end) dominates the landscape, it is a unique experience watching San Francisco 49ers film. Without a stable quarterback presence for most of the season, Shanahan had to rely on a diverse rushing attack to stay ahead of the chains and set up his famous play action and bootleg game.

Defenses nowadays are built to stop 11 personnel, often leaving their nickel on the field for a majority of the snaps. When facing an offense that focuses on 21 personnel (2 running backs and a tight end), they must bring in a more seldom used linebacker to help out in the run game.

Let’s take a look at the 49ers base formation.

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The tight splits of the split ends add a few ways to attack defenses, in both the run game and pass game:

  • They allow for crack blocks on toss/outside zone plays.

  • Down blocks on Duo.

  • They allow for deep crossing routes to get to the other side of the field quickly. From a normal split, the X or Z will take too long to run this route.

The 49ers will always shift or motion to disguise the formation, often by bringing the tight end or fullback in from wide. After this shift, they will often shuffle the fullback right or left to gain leverage for outside zone schemes. The video below shows how the fullback motion helps gain leverage for the outside zone play.

To prevent defenses from catching on, Shanahan will also use the motion to seal up the backside on inside zone. The fullback will perform the backside cutoff block to allow the tackle to get to the next level. The video below shows this version of their inside zone play.

The 49ers will also use the fullback as a lead blocker on inside zone, and have the tight end “slice” across the formation to seal the backside end.

With the arrival of Jimmy Garoppolo, Shanahan added a wrinkle to this inside zone scheme. Instead of using the fullback to block the backside end, he “bluffs” the end and wraps around for the linebacker. The quarterback will read this backside end for a give or keep. The Zone Bluff was a staple in San Francisco when Colin Kaepernick and Jim Harbaugh were in town.

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This play, used sparingly, is an effective wrinkle in short-yardage situations. The video below shows the play, with an unintended result. The Houston Texans’ Jadeveon Clowney uses his technique to close down on the left tackle. Once he realizes it’s a QB keep, he uses his superior athleticism to make the play. This is a lesson that great athletes can often overcome great schemes.

The 49ers can also call the Duo concept out of this formation. The play will be called to the tight end side. The fullback will kick out any D gap player on the frontside. Most NFL teams will call this without a fullback, so this version is relatively unique.

As a guy who loves to throw the ball, I couldn’t keep a few of the neat play action concepts out of this article. The most common play action concept is the “Deep Cross.”

The deep cross provides the quarterback with a simple three level read. The No. 1 receiver on the frontside will run a post or corner. The deep cross will come from the backside, and a back or tight end will leak out, or “slide” across the formation to become the receiver in the flat.

Shanahan will call the Deep Cross a few different ways. The first diagram below shows the drop-back version to the strength of the formation, and the second shows his bootleg away from the strength.

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His variations for this play are endless, and the open receivers jump out on film. The success of these plays will prevent the defense from selling out to stop the run, creating a compounding effect for the offense.

When the defense clamps down on the deep crosses, Shanahan uses a few concepts to take advantage of this. The video below shows a play that gets the fullback matched up on a vertical route, on a run-first defender. The man-match coverage across the board prevents the corners from sagging off the deep curls.

Kyle Shanahan continues to be one of the top play callers in the league. With a full offseason to work with Jimmy G, the world will expect big things next September.

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