IRVING, Texas – To this point in his brief career, it's easier to talk about what Ryan Russell hasn't done than what he has.

Drafted in the fifth round last spring, the Purdue pass rusher was a game day inactive for 10 of his first 11 games as a rookie. His debut season ended in forgetful fashion when he was placed on injured reserve with a month left to play.

To be brutally honest, if Russell's 2015 season was memorable for anything, it was probably his penchant for infuriating defensive coordinator Rod Marinelli during Cowboys practices.

"I don't think it's possible to get harder on me than he was last season," Russell said.

Taking all of those things into account, it's all the more impressive to see the second-year defensive end during Cowboys OTAs. With DeMarcus Lawrence still recuperating from an offseason back surgery, it's Russell who is receiving the bulk of the first-team snaps at left defensive end – a far cry from where he was just seven months ago.

"Last year I played a lot of both sides," Russell said. "This year I'm working mostly on left end and just trying to get in those reps with those guys – going against a lot of starters and going out there with the ones."

Russell is turning heads to this point in the process. While other names like David Irving and Jack Crawford have rotated behind him, Russell has largely been a fixture in the lineup when the first teamers take the field.

"I know he didn't really play a lot last year, but you see a lot of potential with him," said newly-signed defensive tackle Cedric Thornton. "He is kind of like me in that he's out to prove himself."

It's even been enough to draw praise from Marinelli. To be fair, the Cowboys' pass rush guru was measured in his assessment of his young end – noting that the fully-padded practices of training camp are still two months away. But it's still quite a contrast from last year.

"I just think I see some maturity in him, how he's handling it," Marinelli said. "This is non-pads -- we'll make a decision in camp. But I like what he's doing."

That isn't exactly a glowing review, but again – given where Russell was with Marinelli just last year, it's certainly a start. Russell said he's learned not to take any criticism personally, and he's positive it's made him a better player.

"I love Coach Marinelli, definitely. He gets the best out of me. He was hard on me last year, but it's all coming together – this year, especially," he said. "I feel like a completely different player, so I listen to everything he has to say. Whether he's yelling at me or he's just talking to me one-on-one, it's always valuable information."

Hopefully for the Cowboys defense, Russell continues his upward trajectory at training camp. Even once he's recovered from his injury, Lawrence is still facing a suspension to start the season. Fellow starter Randy Gregory is also projected to miss the first four games of the season with his own suspension.

Those losses have prompted plenty of speculation about who will anchor the line in the meantime. From the looks of it, expect Russell to have a say in the competition at left end.

"I'm just trying to hone in and be good at that left side," he said. "With some of the suspensions and things going on, and with my personal ability, I think that's where my best fit is."

For a pass rush with so many questions, it could be big if Russell helps provide an answer.