Pettrey sustained the injury while running downfield on kickoff coverage in Saturday's game against New Mexico State. There's hope he could return in time for Ohio State's bowl game.
Pettrey leads the Big Ten in kicker scoring with 8 points per game and has converted 13 of 17 field-goal attempts and 28 of 29 extra-point attempts. He's a weapon from long distance, connecting on 6 of 8 field-goal attempts from beyond 40 yards.
Junior Devin Barclay will take over the kicking duties for Pettrey after connecting on 1 of 3 attempts against New Mexico State. Freshman Ben Buchanan also is a possibility at kicker.
Adam Rittenberg covers Big Ten football for ESPN.com. He can be reached at email@example.com