In the first half of Saturday's game against Indiana, Ohio State running back Miyan Williams had to be carted to the locker room because of a leg injury.
Williams had already rushed for 147 yards and a touchdown when he went down awkwardly on his ankle after a 4-yard gain in the first half.
Williams has carried the load for the past two games. It could be a problem if both experienced backs are out for the Michigan game.
Williams ran 48 yards for a touchdown in the second quarter, his fourth 100 yard game of the year.
Dallan is the primary backup to Williams.