Williams already had rushed for 147 yards and a touchdown when he went down awkwardly on his ankle after a 4-yard gain with 2:17 left in the first half and the No. 2 Buckeyes leading Indiana 28-7.
Williams has carried the load the last two games with TreVeyon Henderson sidelined with an injury. Ohio State hasn't disclosed details of Henderson's injury, but it could be problematic if both experienced backs are on the shelf for the matchup with No. 3 Michigan in two weeks.