ESPN College Football

The sudden volatility of Oregon State's quarterback situation may be coming at the worst possible time.

Coming off their first loss, the 13th-ranked Beavers turn back to Cody Vaz under center against what's certain to be an angry Arizona State defense Saturday night in Corvallis.

Vaz will start at quarterback for the Beavers (6-1, 4-1 Pac-12) after Sean Mannion's four-interception nightmare led to a 20-17 loss at Washington last week, keeping Oregon State from the first 7-0 start in school history. It was Mannion's first game back since missing two games after minor knee surgery.

Vaz entered late and threw a game-tying touchdown pass with 4:58 left before Washington kicked a late game-winning field goal. Vaz was 7 of 11 for 97 yards in relief of Mannion, who set school records for pass attempts (66) and completions (40) for 341 yards but also threw four picks in a 35-20 loss at Arizona State last season.

"Obviously, it's one of those things that's not easy," Oregon State coach Mike Riley said. "You look at the integrity of the competition and you try to make a decision for the team that's right this minute. We think Cody's playing a little bit better right now and deserves the start."

The junior also showed promise in two previous starts while Mannion was out, compiling a 152.4 quarterback rating and throwing for 506 yards and three TDs in wins over Brigham Young and Utah.

"We're supporting each other, we're both in this together," Vaz said. "I told him that after the game on Saturday.

"We're both each other's biggest fan. No matter who is playing, we're both going to be on the sidelines trying to help each other out."

Vaz will face his toughest test of the season against a Sun Devils team that leads the Pac-12 in total defense (322.0 yards per game) as well as pass defense (148.4).

But Arizona State (5-3, 3-2) has looked much more vulnerable in back-to-back losses, giving up a combined 88 points against Oregon and UCLA. Both racked up 450-plus yards of offense after the Sun Devils allowed no more than 332 yards to any of their previous opponents.

"We're coming off way too many mental mistakes on defense," coach Todd Graham said. "We have to get those things corrected. We have a chance to redeem ourselves this week."

The possible returns of several injured players could help the struggling unit. Graham hopes starters Will Sutton, Junior Onyeali and Steffon Martin will all be able to play Saturday. Sutton didn't play against UCLA after leaving the Oregon game, and Martin and Onyeali were knocked out of the contest against the Bruins.

Sutton's 8 1/2 sacks lead the conference.

Arizona State will also have to worry about a Beavers defense that is stingy in its own right. Oregon State is second in the Pac-12 in total yards (344.1) and fifth in the country in rushing defense (83.4 ypg).

Sun Devils quarterback Taylor Kelly played one of his best games against UCLA, completing 25 of 35 passes for 315 yards and four touchdowns. He will also have to be cognizant of Oregon State's Scott Crichton, whose eight sacks are right behind Sutton for the conference lead.

Oregon State has won its last three games in Corvallis against Arizona State, with the last two being decided by a combined five points.

The Sun Devils haven't beaten a ranked team on the road since 2002.