PROVO — It was shaping up to be a magical season for Oregon State at the start of the week.
The Beavers are undefeated (4-0) and ranked in the Associated Press top 10 for the first time since August 2001.
Then coach Mike Riley casually mentioned to reporters Monday that sophomore quarterback Sean Mannion — who threw for 379 yards and 433 yards, respectively, in victories over UCLA and Arizona and is on pace to break the school record for passing yards — is out indefinitely with a left knee injury.
Of course, it could still be a magical season for No. 10 Oregon State, which visits BYU Saturday (1:30 p.m., MT, ABC), but the dynamics have changed.
The Beavers will have to go on with backup QB Cody Vaz, who hasn't taken a snap in a game since 2010.
So what's the difference between the 6-foot-5 Mannion and the 6-foot Vaz?
"He's not much of a different player than Sean," Riley said. "He's just shorter."
Vaz posted a 24-5 record as a starter at St. Mary's High in Stockton, Calif., and was the Stockton Record player of the year after the 2008 season before enrolling at OSU.
The Beavers say they believe in Vaz, despite his lack of experience.
"He's smooth, he's calm — you can tell he's out there with confidence," said OSU cornerback Jordan Poyer. "He's got a nice ball. A lot of people think he's short, but he reads coverages really well."
"This guy is ready to go and he's going to help win the game for us," Riley said. "Cody is a pretty cool customer. Nothing's going to change. He knows everything we do and he's practiced it all. He's always been ready."
Vaz didn't expect to sit on the bench during his time at Oregon State, like he has up to this point in his career.
"It's a tough situation and I knew that one day I'd get an opportunity, so here it is," said Vaz, who has completed 6 of 17 passes for 48 yards as a backup at OSU. "I just have to make the most of it."
What makes Vaz's first start more challenging is that it's on the road against a BYU team that is ranked No. 1 in run defense, No. 5 in total defense, and No. 3 in scoring defense.
The Cougars say a change at quarterback doesn't change their preparation for Oregon State.
"It's the same offense. I don't see why they will change," said linebacker Kyle Van Noy. "We have the same game plan. They'll probably run the ball more."
"We're still watching the same film. I don't think we have film of (Vaz) actually playing," said linebacker Brandon Ogletree. "We're just going in like we're playing against Oregon State and getting ready for what they do, not necessarily what their quarterback does They're definitely moving the ball pretty well. We don't focus on them as much as we focus on us. So as long as we do what we do, I think we'll be (all right)."
The Beavers are passing for 339 yards per game, which is No. 8 in the nation, and rushing for 118 yards per game, which is No. 103 in the country.
"It will still be formidable no matter who's playing quarterback for them," said coach Bronco Mendenhall. "They're a good team. That's why they're voted 10th (in the polls) and they're undefeated. It's not easy to do that. They'll be good enough."
OSU freshman running back Storm Woods has rushed for 347 yards and two touchdowns, while wide receiver Markus Wheaton has caught 36 passes for 498 yards and four TDs.
"They run it effectively. They run it well when they choose to," Mendenhall said. "What they do this week, I'm not sure. But the scheme is good enough if they want to do that."
"They're very balanced. They can throw the deep ball and they can run the ball," said Van Noy. "Their line is big and their skill guys are really good. I'm sure this new quarterback is going to come out with all the confidence in the world with his teammates playing at a high level. It's going to be a good key, to see how well he plays."
Cougars and Beavers on the air No. 10 Oregon State (4-0) at BYU (4-2) Saturday, 1:30 p.m. MT LaVell Edwards Stadium, Provo TV: ABC
Radio: 1160 AM, 102.7 FM