Ohio State quarterback Braxton Miller was hurt late in the third quarter of the seventh-ranked Buckeyes' game on Saturday against Purdue.
Miller, mentioned among the top Heisman Trophy contenders, was completing a 37-yard run when he was thrown to the turf by cornerback Josh Johnson.
Miller didn't get up for several minutes - he was in obvious pain - while he was attended by several doctors and trainers. Eventually he sat up, then stood on shaky legs for at least 60 seconds before he was led to the sidelines. He was later taken to the locker room by cart.
Ohio State did not say what the nature of his injury was.
Miller completed 9 of 20 passes for 113 yards with an interception and ran for 47 yards on 12 carries before leaving the game.