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Anatomy of a play: Detailing the 49ers play action drift concept

This week’s anatomy of a play details the 49ers favorite play action passing game concept, Drift, and the multiple variations of the play.

Los Angeles Rams v San Francisco 49ers Photo by Michael Zagaris/San Francisco 49ers/Getty Images

It’s no secret that Kyle Shanahan loves the play-action passing. It’s an integral part of how he builds his offense, and it’s very effective when combined with the outside zone running scheme in particular. And with a team like the 49ers, which opponents spend much time lately trying to slow down the 49ers running game, play-action can add stress to a defense if they’re goal for the week is keying on the run game and playing more 5-1 and 6-1 boxes to limit what the 49er can do on the ground.

One of the signature plays in Shanahan’s straight drop back play-action passing game is “drift.” It is a quick-hitting play that hits in the zone vacated by linebackers flowing toward the run action. Often the window the quarterback hits is relatively large because the drift route is typically run behind those linebackers closing the line of scrimmage. The drift route is usually run to the backside of the run call but can sometimes be run to the play side.


In 2019, it was one of the 49ers’ most-used play-action concepts with 18 plays called in a variety of ways. Shanahan will typically pair drift with a go route on the opposite side, a swirl route (known as a 7-stop or corner-stop stop route), drift stalk (more on that later), or running drift from the slot. Any receiver can run it, including tight end George Kittle from a nub tight end position on the end of the offensive line.

The most basic way is diagrammed above with the drift route on the backside and a streak route as the alert to the front side. The 49ers under Shanahan have run this from under center and out of the shotgun.

2019 week 12 vs Green Bay, 1st quarter, 10:46

In both the plays in the clip above, pay particular attention to how the run fake draws up the linebackers and opens the zone behind them for the quarterback. This most basic of play-action of concepts opens some of the biggest throwing lanes in any offense. In the first clip, you can also see Jimmy Garoppolo “can” to new play. In that scenario, they had an outside zone run call as their primary call, got a “middle of the field” closed look from the defense, and changed the play to the second play call, drift.

Drift swirl

Another commonly used play is pairing the drift route with a “swirl” route and calling it “drift swirl.” So far, in 2020, it’s the common way for Shanahan to run it.

The swirl route is a great way to run the concept against 2-high coverage if the quarterback doesn’t have the ability to change the play. On the swirl route, the receiver runs the regular corner stem, cuts to the corner for three or four steps, and breaks it off, and sits down in the zone. The route is also commonly referred to as a 7-stop route (7 being the universal number for corner route in the receiver’s route tree).

Week 6 vs LA Rams, 3rd quarter, 2:33

Here in week six versus the Rams, Shanahan has drift swirl called. The 49ers are in a YY formation in 12 personnel with Kittle and Ross Dwelley as the YY combination on the left of the formation. Deebo motions over to the right and then back to the left as Garoppolo snaps the ball.

The Rams are in a disguised 3-under 3-deep behind a five man fire zone blitz.

The fly motion by Deebo opens a throwing lane to Kittle over the middle.

The flat defender has to widen with Deebo once he shows he’s a threat in the flat and this movement open the window for Garoppolo. You can see from the end zone angle just how much of a window Garoppolo has to fire this pass into Kittle for 18 yards and a first down.

Week 7 at New England, 2nd quarter 4:42

The 49ers called the same YY 12 personnel formation with drift swirl again in week seven at New England but just flipped the formation so Kittle and Dwelley were on the right side.

The Patriots were in a 2-high coverage and recognized the formation pre-snap. The hook defender raced back underneath Kittle’s drift route to force Garoppolo to move on to his next read.

The swirl route is the second read in the play so Garoppolo resets and looks left and fires a pass to Brandon Aiyuk who’s able to get open against the corner, who had no underneath help. He’s protecting the deep seam so the swirl route is the perfect zone beater against that coverage.

Drift Stalk

The last variant to look at is “drift stalk,” and it may look familiar to the reader (more on that shortly), but it’s a full field read for the quarterback with a drift route on the backside and a “stalk-rail” by the slot receiver and “drift-takeoff” by the outside receiver to the front side.

Week 3 at NY Giants, 3rd quarter, 6:33

The 49ers have only run this play one time so far this season, and it came in Week 3 versus the Giants. They’re in 21 personnel but line up in shotgun and motion to a 3x1 with Dwelley motioning left to right to the two receiver side. Aiyuk is the single receiver running the drift route with Bourne out wide running drift takeoff and fullback Kyle Juszczyk running the stalk-rail route.

The Giants are in cover-3 so Mullens is going to be looking for the drift route behind the linebackers who came up to play the run.

He finds Aiyuk wide open in the window created by the play action and fast flowing linebackers.

The play also has a nice shot play built into it. If the quarterback comes off his first read, he scans across the field to the drift takeoff (2nd read) and then to the stalk rail (3rd read).

In the above clips, the 2018 and 2019 49ers are running drift stalk where the ball is thrown to the stalk rail. It has gone for four big plays each time it was run (once in 2018, three in 2019), including one touchdown to Richie James in week one of 2019 against Tampa Bay (2nd clip) even though it’s primarily run with Juszczyk on the stalk rail, three of the four clips show Juszczyk as the stalk rail route runner.

While hitting the rail route is a good sign of a quarterback going through his progressions, when an offense is moving in rhythm and is on schedule, the pass will almost always go to the first read, the drift route, because it is nearly always the one that’s open first.