SPOKANE, Wash. (AP) — Washington State starting quarterback Marshall Lobbestael tore knee ligaments in the game against Oregon State and will miss the rest of the season.

There was no immediate word who will start for WSU against No. 6 Southern Cal on Saturday, but former starter Kevin Lopina had recovered enough from a broken bone in his back to practice on Sunday, coach Paul Wulff said Monday.

"We think Kevin Lopina will be ready to go this week," Wulff said Sunday evening.

Lobbestael, a freshman, began the season as the third-string quarterback but started the past three games after Lopina and Gary Rogers were hurt against Portland State. Rogers is out for the season.

Washington State plays the University of Hawaii Nov. 29 at Aloha Stadium.

Lobbestael, known as "The Lobster," has played decently, but Washington State's thin offensive line has left him continuously hounded by defenses. He was injured in the fourth quarter of a 66-13 loss at Oregon State on Saturday.

Trainer Bill Drake said Lobbestael tore both the anterior cruciate ligament and the medial collateral ligament in his left knee. He left the game and did not return.

Lobbestael's recovery is expected to take about nine months, the team said.

Freshman Dan Wagner finished the game at Oregon State. The Cougars are trying to preserve the redshirt season of freshman quarterback J.T. Levenseller, but that may not be possible.

Lopina played in three games this season, completing 54 percent of his passes for 315 yards, with no touchdowns and five interceptions.

If he plays, he will face a Southern Cal defense that is allowing only allowing 9.4 points per game, lowest in the nation.

The troubles at Washington State (1-6, 0-4 Pac-10) run much deeper than quarterback. The Cougars have given up 63 or more points in three of their four Pac-10 losses.

"We're not going to burn any redshirt at this point, and we have some very capable players we are redshirting who could help us right now," Wulff said. "We are too far into the season to hurt the future of the program."

The Trojans (4-1, 2-1) are an early 42-point favorite against a Cougar team that is yielding an average of 45.1 points per game, and 55.6 in Pac-10 games.

Tight end Devin Frischknecht also underwent an MRI on Sunday for an ankle sprain and will likely miss the game against Southern Cal. But starting running back Dwight Tardy is expected back after missing the OSU game with a knee injury.