SEATTLE — If you could shelve the historical implications of Saturday's game against Washington — Oregon State was trying to start a season 7-0 for the first time — the day's biggest storyline centered on the return of quarterback Sean Mannion.
Less than three weeks after having surgery on his left knee, Mannion returned from a two-game absence to start again for the Beavers.
And while he looked like the Sean Mannion of old at times, the reality is this: With the game on the line, coach Mike Riley replaced him with Cody Vaz after Mannion's fourth interception set up a go-ahead touchdown for Washington in the fourth quarter.
Vaz proceeded to lead Oregon State on an efficient seven-play, 76-yard scoring drive that ended when he floated a 29-yard pass to Connor Hamlett, who caught it among two defenders. That tied the game at 17.
After Oregon State kicked a field goal, Vaz was tasked with leading Oregon State into field goal range with 71 seconds left and three timeouts.
The Beavers started the final drive at their own 36, and Vaz quickly completed his first two passes for 10 and 26 yards.
But then he threw two incompletions and was dropped for a sack on third down, bringing up fourth-and-14 from the Washington 42. A delay of game backed the Beavers up 5 more yards, and Vaz's desperation over the middle fell incomplete with 19 seconds left.
Vaz went 2-for-5 on the final drive and finished with one touchdown after replacing Mannion.
In his two previous starts with Mannion out, Vaz completed 62 percent of his passes for 506 yards, including a 332-yard, three-touchdown outing at BYU in his first start.
And now the quarterback position is up for grabs moving forward.
Mannion started the game on a roll, completing six of his first seven passes for 58 yards in the first quarter. He delivered the ball on time and hit his receivers in stride. He looked like the guy who averaged 339.5 yards per game before his injury.
But in the second quarter, Mannion — and his receiving corps — struggled. He completed only 5 of 12 passes and was intercepted twice — both deep in Husky territory.
Mannion also tossed an interception near midfield in the third quarter. On third-and-3, Mannion rolled right and fired a pass directly at linebacker John Timu, who returned it for a touchdown. An illegal block during the return erased Washington's touchdown, but the Huskies still kept the ball.
His final interception came when he badly threw behind a receiver, leading Riley to pull Vaz off the sideline on the Beavers' next drive.
WHEATON EXITS WITH INJURY: Oregon State's leading receiver, Markus Wheaton, left the Beavers' 20-17 loss to Washington with a head injury in the second quarter after taking a big hit.
Wheaton hauled in a pass between three Husky defenders, but safety Sean Parker delivered the blow right as Wheaton pulled the ball into his body. The hit popped the ball free, and Justin Glenn intercepted it.
Replays showed Wheaton going limp upon impact. He stayed on the ground for a couple of minutes, but got up and walked off the field on his own. He returned to the Oregon State sideline without his pads and wore a sweatshirt.
He had two catches for 25 yards before leaving.
Wheaton entered the game leading Oregon State with 48 catches and six touchdowns while ranking second on the team with 654 receiving yards.
Richard Mullaney, a redshirt freshman listed as Wheaton's backup on the depth chart, played in just his fourth game and hauled in a 45-yard pass on third-and-5. That catch led to Trevor Romaine's 29-yard field that tied the game at 10 in the third quarter. It was just Mullaney's second catch of the season.
EXTRA POINTS: Oregon State didn't score in the first half of a game for the first time all season. The Beavers gained 110 total yards in the first half compared to 158 from the Huskies but two Mannion interceptions halted drives in Washington territory. ... The Beavers had won seven of their last eight meetings against Washington coming into Saturday. Their last loss to the Huskies came in 2010, when Oregon State lost 35-34 in double overtime. Washington now leads the all-time series 59-34-4.