Watch: Justin Fields uses “Y Leak” for his first NFL touchdown pass

Justin Fields’ first NFL touchdown pass came on one of the most effective play calls in the NFL. Why does “Y Leak” work so well?

Bears rookie quarterback Justin Fields had already run for a touchdown in his NFL debut against the Dolphins, and with 3:52 left in the third quarter, Fields hit tight end Jesse James for a 30-yard touchdown pass — Fields’ first at the professional level. It’s interesting to see how this play was designed, and why it worked so well in this case.

The Dolphins were throwing ton of man coverage at Fields, and one of the sure ways for any mobile quarterback to beat man coverage is to run against it. Cornerbacks have to turn their heads in man coverage assignments, and when they turn their heads, they leave open rushing lanes for the quarterback. Fields had already run five times for 33 yards and that touchdown when this play was made, and he’d scrambled for 21 yards just two plays before when he didn’t like what he saw in coverage.

So, when the Dolphins saw run-action blocking and Fields rolling to his right with center Adam Redmond pulling out to block on what became the touchdown pass, they might have read this as a designed run. That was their first problem. Their second problem was that James ran the “Leak” route to perfection — on such routes, the tight end should look like he’s running a short crosser away from the play (possibly as a blocker), he should get lost in the mess of players at the line, and then, he should break into the open field. With that, Fields had James as open as he’ll ever see any receiver at this level.

From the overhead view, you can see the Dolphins further flummoxed by the intermediate crosser and deep post run away from the eventual play. There’s also the matter of the running back as the backside hot read — by the time James releases to his route, the defender has committed underneath.

“Leak” is a staple concept in Kyle Shanahan’s 49ers offense, which is why you’ll see similar wide-open backside throws designed by Shanahan.

Defenses are betwixt and between on such plays because they have to defend the boot, they have to deal with the two-man frontside routes, they have to address the backside hot read, and then, they have to adjust to a frontside tight end running a simple crosser and then becoming a deep receiver. It’s a lot to handle, and kudos to Bears coach Matt Nagy and his staff for dialing it up to Fields’ benefit.

Fields finished his first NFL game completing 14 of 20 passes for 142 yards and a touchdown, and that touchdown was obviously the big play. It’s important to remember how much Fields’ ability to make people miss as an open-field runner set it up.