49ers Film Room: Kyle Shanahan’s Running Game

SPLIT ZONE

Another variant of the zone is known as the “split zone,” a play often run last season by the 49ers under former head coach Chip Kelly. The split zone, as the name implies, aims to “split” the defense in half to create a seam for the ball carrier on the backside of the play.

To accomplish this, offenses use what’s known as a “sift” block, similar to wham or trap block.

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The blocking remains the same for every other lineman regardless if the sift block is added to the inside- or outside-zone runs. The important distinction here is Kyle Shanahan has a variety of ways they run this play.

This particular play is out of 12 personnel but with the tight ends acting as wing backs, akin to what you’d see out of Navy’s triple option:

At the playside tight end comes across the formation to kick out the backside unblocked EMLOS while the back side tight end heads away from the play, taking a linebacker out of the box with him:

As the sift block hits the EMLOS, the left tackle/left guard double team on the defensive tackle flows toward the playside, opening a crease on the backside of the play:

Running back Devonta Freeman hits the open crease for a 10-yard gain: