Friday, though, sophomore defensive tackle Justin Ostrowski hurt his right knee when it collided with a teammate's helmet. Following practice Tuesday afternoon, UW head coach Barry Alvarez acknowledged Ostrowski's injury.
"He's going to be out a while," Alvarez said.
Alvarez said he did not know a timetable for Ostrowski's return. Ostrowski has watched practice the past four days while wearing a leg-length brace on his right leg.
"It does not have to be operated on," Alvarez said, "but he has to stay immobilized for a while", in order to let it heal.
Ostrowski, a 6-foot-5, 305-pounder, is expected to anchor the interior of the Badgers' defensive line this season. He improved significantly during spring practices after playing in 11 games as a reserve lineman last season, and posting five tackles and a sack.
With the team's top defensive tackle on the sidelines, redshirt freshman Jason Chapman has been taking Ostrowski's reps at defensive tackle with the first-team defense. Chapman played both tackle and end last spring, but had been focusing on end prior to Ostrowski's injury. The other first-team players remain Jamal Cooper and Joe Monty at end and Nick Hayden at tackle.
Defensive line coach John Palermo prefers to rotate eight to 10 players, so true freshmen tackle Jeff Stehle may have been in that mix even without the injury to Ostrowski. But now Stehle has been receiving regular reps with the second-team defense, rotating with redshirt freshman Gino Cruse. Another true freshman, Matt Shaughnessy, has replaced Chapman on the second team at defensive end. Mike Newkirk has been a fixture on the second team at right defensive tackle, with Kurt Ware at the other defensive end spot.
"Shaughnessy's really played well," Alvarez said. "He's got some ability. He's very raw. Stehle, he's a big plugger and has ability. Those are guys that I'm sure JP's going to have to work with."
Also Tuesday, Alvarez said that true freshman tailback P.J. Hill had broken a bone "right above his ankle" and had to have a plate inserted to facilitate the healing process.
"He'll be out probably until the middle of October," Alvarez said.
Hill was injured during Wisconsin's controlled, full tackle scrimmage Sunday. On a third-and-three play from the 7-yard line, Hill picked up four yards on an inside run. Though the injury did not look severe initially, Hill appeared to hurt his left leg at the end of the run.
Prior to the injury, Hill was one of the Badgers' most impressive true freshmen, regardless of position. He likely would have entered the season no lower than fourth on the team's depth chart at tailback. In an interview Friday, two days before the injury and just three days into training camp, Hill said that the Badgers' coaching staff had already told him to expect to play this season.
With Hill on the mend, true freshman Jerry Butler may have a chance to work into the depth at tailback. He also is in the mix at kick returner and punt returner. Butler is perhaps generously listed at 5-9, 175 pounds, but on the field he looks like Wisconsin's fastest player at any position.
"I think we're trying to get Jerry ready," Alvarez said. "He's probably fourth down the line at tailback. But he brings something else to the table, that speed of his. Maybe as a returner or somewhere along the line I plan on getting him on the field. I think he can help us somehow.
"He's got that burst. He just has flat-out sprinter's speed. He can wiggle and he's a tough little guy. He's only 175 pounds but he's a tough guy and he's got a burst. He's just got to learn, he's got learn how to play."