LINCOLN, Neb. (AP) — Nebraska coach Mike Riley meant it when he said in the preseason that he wanted one of his three top running backs to do most of the work.

Tre Bryant has 51 carries in two games, Mikale Wilbon has five and Devine Ozigbo has none.

Change might be coming for this week's game against Northern Illinois (1-1). Bryant aggravated his right knee against Oregon on Saturday, and Riley said Monday it would be mid-week until he knows whether the sophomore can play against the Huskies. Riley said Bryant's knee issue has more to do with wear-and-tear than a specific injury.

"His knee is older than his age," Riley said. "We have from the beginning of camp managed Tre in a way we don't overwork him."

Bryant ran 31 times for a career-high 192 yards in the opener against Arkansas State , and Riley said in retrospect that number of carries "might be at the high end of what he should do." Bryant had 20 carries for 107 yards against Oregon before leaving early in the fourth quarter of the 42-35 loss .

If Bryant can't play, Wilbon would make his first career start and be backed up by Ozigbo. True freshman Jaylin Bradley will go into the week preparing as the No. 3 running back.

The Huskers' decision to not play Ozigbo has been a bit of a mystery. Last year, he appeared in 11 games and had the third-most carries on the team, at 97. So far, he's yet to get on the field in any capacity.

"We're not into the rotation deal like we have been in the past," Riley said. "We made a decision to play Tre and then we had to make a decision on who to spell him with, and we chose Wilbon. All three of the backs are improved players from a year ago. Our thought is that whenever Devine is called upon, he will play well, so we just keep coaching him and get him ready."

Riley, as coach at Oregon State for 14 years, typically relied on one back to get the vast majority of carries. He said he's found that backs tend to get stronger as the game continues.

Bryant has been one of the early surprises for the Cornhuskers (1-1). Last year, he totaled 172 yards on 43 carries as the backup to Terrell Newby and Ozigbo. Bryant's two-game average of 149.5 yards ranks second behind Wisconsin freshman Jonathan Taylor's 155 yards a game and ninth nationally, and he's broken runs of 24, 35 and 25 yards so far.

Riley said he knows not playing has been difficult for Ozigbo.

"He has played, he's a good player, he's worked hard, he's gotten better, (but) so has everybody else," Riley said. "We made a decision. It's outside of anything he can do about it. So what are you going to do? Are you going to pout? If you pout, when your chance comes, chances are you won't be ready because you've been thinking about this instead of getting ready for that.

"It's one of those hard things in life. I know it's hard because he cares and he works hard and he's a great guy. But he'll be ready."

NOTES: Safety Joshua Kalu (hamstring) and offensive lineman David Knevel (ankle) are doubtful for the Northern Illinois game. ... After the loss to Oregon, Riley said, "We should be so hungry to practice today. When they look at that film, they should just be sick, and they should want to get out there and work to be better than that."

___

More AP college football at www.collegefootball.ap.org and https://twitter.com/AP_Top25