Defensive line has been an anchor for the Washington Commanders' defense for the past two seasons, but a couple losses to its depth -- Matt Ioannidis and Tim Settle -- had the position looking a bit thinner than normal.
In a recent sitdown with Donaldson, Del Rio laid out part of what he has planned for Mathis. His size, paired with his ability to stop runs and generate interior pressure, leave the defensive coordinator believing he's ready to contribute now.
"He's, at this point, our third legitimate defensive tackle body that we have in the building," Del Rio said.
Take a look at the Washington Commanders' draft class getting fitted for equipment during the first day of rookie minicamp. (Emilee Fails/Washington Commanders)
Mathis, who was a rotational player before earning a starting role on Alabama's defensive line during his senior year, had a career season with 53 tackles and nine sacks. He played a lot of big time football, said general manager Martin Mayhew, against competition in the SEC. That alone gives Mayhew and Rivera confidence that Mathis has the talent to function in their system.
Del Rio expects Mathis to contribute heavily in the run game, where he can use his 6-foot-4, 310-pound frame to clog running gaps and rotate with Jonathan Allen and Daron Payne when needed, but he also expects Mathis to play a role in rushing he passer.
"Obviously with our big [defensive ends] coming off the edge, we need some of that interior push," Del Rio said.
Washington relies on its defensive line to penetrate and disrupt to become anchor points. Mathis will be asked to do the same thing, and while he's not viewed as a player who will simply take up blockers to let others make plays, him doing his job will benefit Cole Holcomb, Jamin Davis and the rest of the team's linebackers.
"We want them to actually penetrate, make the offense have to deal with them and the penetrations and the disruption," Del Rio said. "And then the linebackers will be able to fit off of that."
Still, Mathis' unselfish approach to the game is one thing that stuck out to Rivera. As long as what he does helps the defense as a whole, he doesn't care who makes the play.
"Very unselfish, willing to do the work," Rivera said. "One thing he did very well was he held the point of attack. He absorbed the double teams, allowed the linebackers to run. He allowed them to run and be productive."
It also reminds Rivera of watching linebackers "back in the day" who could disrupt plays.
"That's because they had people in front of them that really knew how to absorb those blocks."
And Mathis is bringing that same enthusiasm he showed at Alabama to help the entire defense with him to Alabama.
"I'm just going to take whatever comes to me and I'm going to go in, just do my job," Mathis said. "Whatever coach asks me, I'm doing it. So whatever my role is, that's what I'm coming to do. And I'm going to put my best foot forward no matter what."