Wisconsin senior nose tackle Olive Sagapolu will miss the rest of the season after undergoing arm surgery, coach Paul Chryst told reporters after Thursday's practice.
Sagapolu underwent the procedure on his right arm on Wednesday. He suffered the injury during a loss to Northwestern on Oct. 27.
"He has been great in how he is handling it," Chryst said. "But you feel bad for him -- any time guys miss games, but particularly seniors."
Sagapolu, who started 26 of 44 games played for the Badgers, had 23 tackles and two sacks this season.
Meanwhile, junior quarterback Alex Hornibrook remains in concussion protocol and is considered questionable for Saturday's game at No. 20 Penn State.
Hornibrook suffered a concussion against Illinois on Oct. 20 and missed the following week's game against Northwestern. He was cleared to play in last Saturday's win over Rutgers, but a first-half hit knocked him out of the contest and he went back into concussion protocol.
Sophomore Jack Coan is being prepared to make his second start of the season. Coan is 25-of-38 passing for 222 yards and two touchdowns.
"The protocol, the steps of it are such that you can do some things," Chryst told reporters of Hornibrook. "But at the same time, you don't want to be in that the whole season. So we'll see if he can, and if not, then obviously Jack will go, and we feel good with the preparation that he's had."
Hornibrook has passed for 1,343 yards, 11 touchdowns and eight interceptions this season.