USC linebacker Morgan Breslin, who began the season as a candidate for several postseason awards, will have hip surgery that will sideline him the rest of the regular season, interim Coach Ed Orgeron announced Wednesday.
"There is a chance he may be back if there is a later game down the road," Orgeron said.
Orgeron made the announcement on a day when defensive end Leonard Williams was absent for the second consecutive practice.
Williams, the team leader in tackles and tackles for losses, is nursing a shoulder injury and is questionable for Saturday's Pac-12 Conference game at California, Orgeron said.
The 6-foot-2, 250-pound Breslin transferred to USC from Diablo Valley College in spring 2012. He was an All-Pac-12 defensive lineman as a junior, recording a team-best 19½ tackles for losses, including 13 sacks.
Breslin moved to a stand-up linebacker spot under new defensive coordinator Clancy Pendergast, but he sat out the season opener against Hawaii because of a foot injury. He started the next four games and then was sidelined against Arizona because of the hip injury. He returned against Notre Dame, but he has sat out the last two games.
Breslin has eight tackles for losses, including 4½ sacks, which rank third on the team. Linebacker Devon Kennard has seven sacks, Williams five.
Orgeron reiterated a statement he made earlier this week, describing Breslin as one of the "favorite" players he has coached in 27 seasons.
Pendergast said Breslin has been "sorely missed."
"He brought a lot of things to our team, not only as a very good player but as a good teammate," Pendergast said.
Junior J.R. Tavai has been productive in Breslin's place, registering 10 or more tackles in two of the last four games.
Pendergast was defensive coordinator at Cal the previous three seasons but was not retained after former coach Jeff Tedford was fired.
"I enjoyed my time up there," Pendergast said, adding, "I had a lot of fond memories and I'm looking forward to going up there and playing."
Cal ranked first in the conference in defense in 2010 and 2011 but was 10th in 2012.
USC's defense is currently ranked first in the conference, giving up 323 yards a game.
Cal, which is 1-8 overall and 0-6 in Pac-12 play, ranks sixth in the conference in total offense (462.9 yards per game) and last in scoring (23.4 points a game).
Safety Su'a Cravens said he was"100% back" from a groin injury that forced him to sit out against Oregon State…. Senior right tackle Kevin Graf, who sat out against Oregon State because of an ankle injury, was updated to probable for Saturday's game, but the Trojans might continue with the same alignment that played most of the last two games. Chad Wheeler is the left tackle, John Martinez left guard, Marcus Martin center, Aundrey Walker right guard and Max Tuerk right tackle. "We like the continuity of last week's game," Orgeron said. "We have to see how healthy [Graf] is and how many snaps he can play…. We haven't made a decision yet."