NORMAN, Okla. — In most cases, replacing two record-holders at one position would be cause for concern.

Oklahoma feels as if it is simply reloading.

The Sooners need to fill the slots left open when running backs Samaje Perine and Joe Mixon chose to leave early for the NFL. Perine left Oklahoma as the school's all-time rushing leader, and he's climbing the depth chart with the Washington Redskins.

Mixon, who plays for the Cincinnati Bengals, was the Sooners' leading rusher last season and broke DeMarco Murray's record for all-purpose yards in a season.

The top two candidates to step in appear to be Rodney Anderson and Abdul Adams, but freshman Trey Sermon and junior-college transfer Marcelias Sutton are talented and have made good impressions on the coaching staff. The Sooners have lost freshman Kennedy Brooks for the season with a shoulder injury, but Oklahoma coach Lincoln Riley still feels good about the depth at the position.

"They've been pretty equal the whole way through," Riley said after a scrimmage Saturday morning. "And again, just a very, very competitive room. So not close right now to laying out any kind of order. Again, I think all of those guys are going to have a role."

Riley said he has no problem going with a committee approach.

"We'll definitely play multiple," Riley said. "Will we play all four or is it three? Part of that will depend on how they react in game situations and how they get going."

Anderson is back after missing most of 2015 with a leg injury and all of last season with a neck injury. He is now taking contact in practice and continues to impress the coaching staff.

"He's a physical kid," Riley said. "You see zero hesitation in the way that guy runs. That's not who he is as a person or a player. I haven't seen any hurdles. I've seen a motivated guy who had to knock some of the rust off in the beginning. It's just rapidly getting better and better."

Adams, the team's top returning rusher, ran for 91 yards against both Louisiana-Monroe and Kansas last season and finished the year with 283 yards rushing. Riley said Adams has worked on his weaknesses.

"He had a tremendous spring," Riley said. "Probably one of the most improved guys on either side of the ball. I would just say he's continued to steadily climb."

The Sooners are set at fullback. Dimitri Flowers actually leads returning Oklahoma backs in yards from scrimmage, with 315 to Adams' 308. He can also carry the load — he ran 22 times for 115 yards and caught three passes for 34 yards in a win over Iowa State last season.

All of this has quarterback Baker Mayfield, a Heisman finalist last season, excited about the upcoming season. He knows the importance of a balanced attack to keep defenses honest.

"It's exciting to see all the things they do well," Mayfield said earlier this month. "I think Rodney and Trey Sermon bring in the pass-game element. They add a lot to that. I think Marcelias is just so explosive that he can take it to the house any time he touches the ball. It's a deep running back room. I think the competition is unlike any other we have. It's exciting to see."