ESPN College Football

When this season began, neither Kevin Hogan nor Cody Vaz figured to be starting in a critical Pac-12 matchup.

The quarterbacks could be needed to shoulder heavy burdens Saturday when Hogan and No. 16 Stanford host Vaz and No. 13 Oregon State.

Any chance these teams have of catching unbeaten and second-ranked Oregon in the Pac-12 North standings likely hinges on winning this game. Stanford (7-2, 5-1) and Oregon State (7-1, 5-1) will both be using signal-callers who began the season as backups.

"Usually you're in these positions because your quarterback is playing and playing well," Stanford coach David Shaw said. "But I think also both teams have to do what's necessary to hopefully help their teams win."

Shaw started senior Josh Nunes for the first nine games, but made a change during last Saturday's 48-0 win at Colorado. Hogan entered in relief and completed 18 of 23 passes for 184 yards and two touchdowns while carrying seven times for 48 yards.

The redshirt freshman did well enough to earn his first collegiate start.

"We knew we were going to give Josh the first two series and give Kevin the next two series and see where we went from there," Shaw said. "And Kevin took the ball and ran with it."

Nunes, who had big shoes to fill in replacing top overall NFL draft pick Andrew Luck, has been inconsistent with 10 touchdowns and seven interceptions.

Oregon State coach Mike Riley began the year with Sean Mannion as his starter for the second straight season. Mannion got hurt Oct. 6 and returned to throw four interceptions in the Beavers' lone loss, 20-17 at Washington on Oct. 27.

Vaz became the starter the next game and threw for three scores in last Saturday's 36-26 win over Arizona State.

"We've had an unusual situation in that Sean got hurt and that Cody Vaz, who I've always thought competed well to be the starter here, got an opportunity here and took of advantage it," Riley said. "It's always a difficult thing to choose between two good players."

Vaz will have to watch out for Stanford safety Ed Reynolds, who is tied for the FBS lead with three interception returns for touchdowns, including one each of the last two weeks.

Both passing attacks figure to be in the spotlight because these teams have the conference's best run defenses. Stanford leads the country in allowing 55.8 yards per game on the ground while Oregon State is fifth at 91.8.

The Cardinal have actually yielded a total of minus-34 rushing yards during their three-game win streak and they also limited then-No. 2 Southern California to a season-low 26 in a 21-14 victory Sept. 15.

"It's crazy, I mean it is really crazy," Riley said. "They are imposing to watch. What they did to USC was very impressive defensively."

The Beavers seem to have an edge in the passing game based on the production of receivers Brandin Cooks and Markus Wheaton. Cooks is second in the Pac-12 at 113.3 yards per game and Wheaton is fourth at 98.4.

Both went over 100 yards last week, as Cooks had six receptions for 116 and one touchdown while Wheaton scored twice among his four catches for 108.

"The thing with the kids from Oregon State, they're so quick, so explosive," Shaw said. "You have to be ready for them coming off the ball, screens, fly-sweeps and just when you think everything is short, they'll run right by you."

Cardinal running back Stepfan Taylor has a tough matchup against the Beavers' stout defense. Taylor is fourth in the conference with 105.2 yards per game, but he's totaled just 101 over his last two contests.

The senior, however, has amassed 210 yards in helping Stanford win its last two meetings with Oregon State. He needs 53 to notch his third straight 1,000-yard campaign.

The Beavers' preparation has been hampered by the lack of film on Hogan, who had thrown only one pass before last week.

"I think Hogan is a very good athlete and I don't think it changes a lot in what they plan on doing," Riley said.