The mechanics behind an Aaron Donald predation event.

On the surface, a defensive lineman stuffing the run looks similar to a massive predator stalking its prey from a hidden vantage point. An orca emerging jaws-first from dark water to snatch a seal breaching the surface. A lion exploding through the brush and pouncing on a grazing impala.

Aaron Donald cutting through the line of scrimmage and wrapping an unsuspecting Jay Ajayi.

It’s an awesome sight. If you imagine it from the seal, impala, or Ajayi’s point of view there’s a split-second of terror. But if you’ve ever lived through a predation event as the prey or more likely, been stuffed by a defender playing football, you’re rarely cognizant of of what happened until it’s almost over.

What continuously surprises me about the predatory habits of defensive linemen is their economy of movement. When imagine them covering 4-6 yards within a blink of an eye, we don’t consider how little movement actually takes place to facilitate these huge bursts up field.

Michael Bennett illustrated this against the Cardinals in my first NFL Lens on defensive tackle play. Donald demonstrates the same concept.

If you weren’t familiar with line play, you’d probably expect Donald to explode off the line of scrimmage and, depending on his plan, get into or around the frame of the guard as soon as possible.

Much of what Donald does here begins with his understanding of the game. Donald’s actions are based on his pre-snap alignment with his teammate to his left and the blocking scheme he’s facing.

Donald knows his teammate will take on the center, which will temporarily stop the slant of the Dolphins’ offensive line to the left. The center will eventually get help from the right guard but it’s that initial collision with the center that will open a crease to the left guard’s inside shoulder that Donald wants to access.

Donald also knows this if this play is a run, it’s likely a zone play with a reach block from the left guard. It will mean the left guard wants to get his hands on Donald as soon as possible, push the defender downfield, and angle him to the left.

Knowledge is power and Donald uses this information to tailor his move to this anticipated outcome. As the snap, the guard’s arms are already shooting toward in anticipation connecting with Donald and taking the defender downhill and to the left.

Donald comes off the ball quickly with his pads down and leaning towards the guard, which gives the offensive lineman what that lineman wants to see. It’s an illusion.

Donald’s left foot moves a yard and plants into the ground just long enough to get his feet even. With his feet under his pads and even, Donald pivots his inside foot so his toe is facing to the right.

This foot position gives him a base to turn his hips and slide inside the guard. It’s a small move, but it’s an explosive one.

The way a boxer sets his feet and points his toe is the grounding point for an explosive move—be it a feint or a punch. It’s the same with a defensive lineman working in a confined space.

In this case, Donald is feinting to the left and his “punch” is an arm-over or swim of the lineman.

What’s notable for those scouting linemen is that the feet are almost always the beginning of the story. If a lineman does good work with his hands, the source of his power, position, and leverage are his feet.

It’s not just how quickly the defender moves his feet, but how precise they are at accomplishing a task. Explosive movement may come from muscle density but it’s enhanced and refined to a specific task with technically sound positioning.

Examine the placement of the toes, feet, knees, and hips when a running back makes an explosive cutback or the position of these body parts with a receiver’s stance at the line of scrimmage against a press corner. You’ll see this idea covers a wide range of positions on the football field.

Donald wins this move 6-12 inches from the line of of scrimmage and despite the lineman leaning for him, Donald is the first to make contact with his outside arm to set up the swim. There’s no way Donald gets first contact if his footwork lacked the economy to set up his plan with three steps covering no more than a yard.

The rest is the product Donald’s teammates getting a good push to the left that forces an Ajayi cutback. Donald pursues as Ajayi cuts back and it’s the chocolate and peanut butter goodness the we know as stuff or a tackle for a loss.