It may not prevent him from playing next week, however.
Miller, mentioned as one of the top contenders for the Heisman Trophy, left the third-ranked Buckeyes' game against San Diego State after being pinned between tacklers.
"We had a long discussion on the sideline. I think he could have (returned)," Ohio State coach Urban Meyer said after the Buckeyes' 42-7 win over San Diego State. "But the things that make him dangerous are his wheels and I don't think it would have been (the same). So we decided it was best not to.
"I think there's a chance he'll be ready next week."
The Buckeyes play at California in their first road game.
Miller was taken to the locker room on a cart while grim-faced Buckeyes fans looked on. But shortly before the end of the first quarter, in the lull after Ohio State had scored its third touchdown, he jogged across the field to the Ohio State bench and received a loud ovation.
Meyer said Miller had a knee sprain and would be evaluated.
The junior carried on fourth and 1 at the Aztecs 12 on Ohio State's seventh offensive play of the game. He cut inside right end and was hit by defensive back King Holder and middle linebacker Jake Fely, Miller's helmet popping off as he fell.
He lay on the field on his back for a moment, holding his head.
A team doctor manipulated his left knee at one point and he grimaced in pain. Miller was then taken by motorized cart to the locker room.
With Kenny Guiton taking his place, the Buckeyes scored on the next play for a 7-0 lead and were never threatened while winning their second game of the season.
Guiton also threw two touchdown passes and ran for another in the most substantial playing time of his career.
Guiton, a senior, had taken over for an injured Miller late in last season's eighth game—against Purdue. He led the Buckeyes to an improbable touchdown and then threw a 2-point conversion pass to force overtime. The Buckeyes won 29-22 on the way to a 12-0 season.
Follow Rusty Miller on Twitter: http://www.twitter.com/RustyMillerAP