Senior Nebraska defensive lineman Greg McMullen is moving on from the sport of football.

Considered the Huskers top returning defensive linemen in 2015, McMullen started 26 consecutive games as a sophomore and junior and has played in 37 games overall the last three seasons.

McMullen took a "leave of absence" from the team last week, and was on the sidelines during Saturday's Red-White spring game.

“Greg McMullen is finishing his degree and has already been accepted and been granted an assistantship in graduate school,” head coach Mike Riley said. “He’s going to work with youth in our area. Since he’s got his degree, he wants to go on with his life. He’s made a decision not to play football any more. Obviously that means an opportunity to play after this. He has really got a vision about where he wants to go and what he wants to do. I’m really proud of him in a lot of ways for what he has done here for this school and this team getting his degree and having a real plan going forward.

"In saying that, we’ll miss him. As a guy around here he’s a really, really good person and a good football player. It’s kind of bitter sweet for sure.”

Senior safety Nate Gerry said McMullen told the team of his decision before kickoff of Saturday's Red-White spring game.

“It’s going to be tough for the team just because Greg is one of those senior leaders, and a lot of people look up to Greg," Gerry said of McMullen. "He’s a good role model for everybody on the team. He’s a veteran player that when you get done in the fourth quarter, he’s one of those guys you want to count on. Having him gone it’s going to be tough. We are going to need a lot of young defensive linemen to step up. I thought the Davis twins had a pretty good spring, and I thought Peyton Newell as well had a pretty good spring.”

Riley also announced at the end of the game that senior defensive tackle Kevin Williams will also pursue being a graduate transfer and won't be back at NU.

“He is choosing a different opportunity to play as a graduate transfer somewhere,” Riley said. “He’s looking for a different opportunity in the scheme of things finding a spot to play.”

The loss of McMullen and Williams leaves the Huskers with senior Kevin Maurice and redshirt freshman Khalil Davis as the two projected starters at defensive tackle, with sophomore Mick Stoltenberg and redshirt freshmen Carlos Davis and Peyton Newell also in the discussion.

Another piece of roster news Riley announced on Saturday was senior offensive lineman Paul Thurston will not be back in 2016, and plans to pursue being a graduate transfer. Thurston only practiced four days with NU this spring because of a class conflict.

"He might be another guy that's looking at the depth chart and wanting to play more and looking at another place," Riley said of Thurston. "He has asked for his (release) and we agreed to talk about it more next week, but I would say for the most part that is final. He's going to find another place. He, like Kevin (Williams) look at the depth chart and see their senior year and they are looking for opportunity."