The Denver Broncos signed Saints defensive tackle Malcolm Roach, 25, to a two-year, $7 million contract.

Roach joined the Saints in 2020 as an undrafted free agent out of Texas. He immediately joined their defensive rotation. He never became a starter but contributed significantly in all four of his seasons with the Saints.

Why did the Broncos invest in Malcolm Roach?

This play is why…

(Roach is No. 97.)

Roach is a run defender. He’s a role player, but he plays his role well. According to PFF, Roach had the best run stop rate of any interior defensive lineman in the NFL last year.

Roach has great upper-body strength. In the next clip, he gains leverage inside his gap. Then he holds off the offensive lineman with one arm, using the other to control the lane.

This time, Roach’s assignment is to plug the gap between the left tackle and left guard. He gains leverage. Then, when the running back commits to running inside, Roach is able to outmuscle the guard and fight back to the inside.

This time, he doesn’t need as much power to get off the block. He makes a simple move to separate from the block and make the tackle.

In the next clip, Roach is doubled immediately. The center helps the guard gain leverage. As soon as the center extends to the second level, Roach is able to grind his way inside and contribute to closing the running lane.

Here’s a similar play, with Roach collapsing the running lane again.

Roach is stout enough to play nose tackle, but his “stoutness” is probably adequate more than it’s exceptional. Occasionally, a double-team will knock him off his spot.

But even if his lower body isn’t notably strong, his quickness makes up for it. Here’s an example of Roach moving in space. You can almost tell that he was a linebacker in high school and occasionally at Texas, too.

Roach’s is a high-motor player, and his exceptional mobility for a run-stuffing defensive tackle helps him provide pursuit downfield.

Roach’s mobility shows up the most in outside zone runs. He flows with stretch runs. He doesn’t make the tackle in the next clip, but you can see him flow with the play and then burst into space.

Roach hasn’t provided much as a pass-rusher. He generally holds his ground and jumps to try to bat the pass. He got a hand on three balls last season.

For what it’s worth, Roach is rarely on the field in passing situations. His job is to stop the run, and if the offense decides to pass when he’s on the field then he shifts his attention. It’s a different situation than a pass-rush specialist who is thinking pass-first when he’s on the field.

Regardless, Roach hasn’t proven anything as a pass-rusher. Sometimes Roach will push a pass protector back a couple of steps, but I wouldn’t call him a pocket-collapser, either.

Roach has major strengths that will help the Broncos immediately. He can shed blocks easily thanks to a jacked upper body. His quick feet make him a monster against zone runs, allowing him to out-quick offensive linemen as well as outmuscle them.

He isn’t a true nose tackle. He’ll lose ground occasionally, especially when double-teamed. But he’s a gap-controlling tackle who can stuff runs without any help.

Roach only has one career sack, and that isn’t a fluke. Pass-rushing isn’t his game. He’s a rotational run defender who typically played about 40% of the Saints’ defensive snaps. He started a handful of games, but he was never a full-time starter.

Barring a surprise addition, Roach figures to be part of the Broncos base 3-4 front. He could play tackle or three-technique, with DJ Jones taking the other role. Roach won’t be part of the Broncos’ rush packages, but he could earn a heavy cut of the neutral-situation nickel snaps in a rotation with Jones and Zach Allen.

Keeping Roach’s workload light might be the smart play. The Saints placed Roach on injured reserve three times during his four-year stretch in New Orleans. If Roach stays healthy, the Broncos could creep his snaps up toward 50%.

(Cick here for our breakdown of new Denver Broncos safety Brandon Jones.)