LINCOLN, Neb. -- Nebraska running back Ameer Abdullah might miss the rest of spring practice because of a knee injury.

Coach Bo Pelini said after practice Monday that Abdullah "tweaked" a knee and would be out at least a couple weeks. Pelini added it's possible the rising junior won't return this spring.

Abdullah was the Cornhuskers' top rusher in 2012, running for 1,137 yards as the replacement for the injured Rex Burkhead. Burkhead was a senior last season, and the Huskers are without Braylon Heard, who is transferring. That leaves sophomore Imani Cross as the only experienced I-back.

Pelini also said sophomore offensive linemen Ryne Reeves would miss the rest of spring practice because of an ankle injury. Reeves appeared in four games last season as a backup guard.

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