Nebraska Cornhuskers senior running back Rex Burkhead could miss Saturday's game against Michigan after reaggravating a left knee injury for the second time in three weeks.
Michigan starting cornerback J.T. Floyd will miss the remainder of the season after sustaining an ankle injury in Tuesday's practice.
Michigan junior wide receiver Martavious Odoms will miss extended time after suffering a broken foot in Saturday's loss to Michigan State.
Michigan could be missing receiver Roy Roundtree and safety-linebacker Carvin Johnson when it visits rival Notre Dame on Saturday.
Michigan Wolverines senior cornerback Troy Woolfolk suffered a "lower body injury" in Tuesday's practice and had to be taken to a local hospital.
Penn State will be without its second leading rusher Saturday when it hits the road to face Michigan (ABC, 3:30 p.m. ET).
Michigan quarterback Steven Threet is listed as doubtful for Saturday's game at No. 10 Ohio State because of a shoulder injury.