CORVALLIS -- Forgive him, but sometimes Oregon State offensive coordinator Danny Langsdorf forgets that quarterback Sean Mannion is just a sophomore.

In the past few weeks, fans have probably forgotten that, too.

When Mannion came back from knee surgery on Oct. 27 against Washington, many of the OSU faithful probably expected the same old Sean, the second-year starter who was spectacular against Arizona and UCLA.

But since Mannion's return, he's thrown nine interceptions and OSU has gone 2-3. He was benched for two games in favor of backup Cody Vaz, but brought back when Vaz hurt his ankle Nov. 10 at Stanford. (Both are expected to play this weekend against Nicholls State.) In summing up the Beavers' season the past five weeks, fans are probably wondering one thing:

What's wrong with Sean Mannion?

The answer, according to Langsdorf, is complicated.

There was lots of talk coming into 2012 with some wondering if Mannion would make the typical "sophomore jump" that lots of past quarterbacks have made in Mike Riley's system. But most of those quarterbacks didn't play as freshmen, like Mannion did in 2011.

"He's played a lot of football, but he's also young," Langsdorf said. "I forget that sometimes, too, because it feels like he's played a lot. And he has, but he's also got a long ways to go."

Before the Washington game, Mannion was on track for a great season, statistically. Since then, though, his passing efficiency has dropped dramatically. Last season as a freshman, Mannion completed 305 of 473 passes for 3,328 yards and 16 touchdowns. He also tossed 18 interceptions, finishing with a 127.1 pass efficiency rating, ninth best in the Pac-12.

So far this season, Mannion has completed 180 of 286 passes for 2,215 yards and 13 touchdowns. He's thrown 13 interceptions, but he's also only played in eight games. His efficiency ratingis 133.9. (Vaz, by comparison, is at 140.3.)

After a Civil War nightmare that featured four picks, Mannion said he needs to remember that he can't catch up in one play.

"I think I need to keep in mind that while we may be down a score or two, there's no need to force it. There's no 17-point touchdown pass to be thrown," he said. "You have to take it one play at a time."

It's a cliché to be sure, but one that would serve Mannion well.

"At times he's trying to do too much, he's pressing a little," Langsdorf said. "He needs to relax a little bit and not try to do everything by himself. He's got 10 other guys out there with him."

Almost every OSU offensive player has expressed confidence in Mannion. Langsdorf acknowledged that as a coach you worry if turnovers are getting to your quarterback mentally, but said Mannion's poise is pretty good.

"He doesn't get too high or too low," Langsdorf said. "He's often ahead of me in terms of what happened, saying, 'I know I did this' or 'I misread that.' A lot of times, he's got a pretty good handle on what happened."

And in that way, Mannion reminds Langsdorf of another Oregon State quarterback: Former All-Pac-12 player Sean Canfield.

Langsdorf and Mannion spend a lot of time talking about Canfield, and why he was so efficient in 2009, his senior year. Canfield completed 303 of 446 passes that season for 3,271 yards and 21 touchdowns, throwing just seven interceptions.

"Canfield was effective because he'd push the ball down the field to an open guy and if it wasn't clean, he would dump the ball," Langsdorf said. "He threw 78 balls to Quizz that year, and a lot of them were checkdowns. Mannion has to get to that point, too."

Continued film study will help. Langsdorf said Mannion must get better at understanding a pre-snap read vs. a post-snap read.

"Sometimes he hasn't recognized the rotation of the coverage," Langsdorf said. "And that's given him some problems."

But all the Xs and Os and interceptions aside, Langsdorf and Riley still believe Mannion has the chance to be a superstar. The guy who led OSU to huge road wins hasn't disappeared. He just needs to take a deep breath.

"We do have a lot of confidence in him," Langsdorf said. "He has to keep learning from those mistakes, cut down on turnovers and he'll be fine."

Notes:

Receiver Brandin Cooks (knee contusion) practiced Thursday, but his status is still up in the air ... Receivers coach Brent Brennan has been named one of three semifinalists for the Football Scoop’s Wide Receiver Coach of the Year.

-- Lindsay Schnell (I came, I saw,

)