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Any game played the week after Adrian Peterson gets hurt is going to be a challenge, but Oklahoma has a few other hurdles to clear while trying to define its offense without its star. Colorado comes to Norman a week after its first win of the season, which could have the Buffaloes on an emotional high.

And the Sooners must find a way to establish the running game with a committee of backs less experienced and less talented than Peterson. Adding to that challenge is Colorado's run defense, which ranks ninth in the country, allowing just 77.4 yards per game.

The pressure to move the ball likely falls on senior quarterback Paul Thompson, who has warned his team about being fooled by Colorado's 1-6 record.

"They're real close to having some wins," Thompson said of Colorado, which lost 14-13 to a then-highly ranked Georgia team.

"If we sit there and look at their record, then we'll get beat. They're a good team."

But not against the pass. Colorado ranks 102nd in the nation against the pass, giving up 245.6 yards per game. Only six teams have allowed more touchdown passes than Colorado's 13.

Colorado's defense will be the key for keeping the game close Saturday.

The Buffs offense averages a Big 12 Conference-worst 15.7 points per game.

• Another running QB: OU defensive end Larry Birdine rolled his eyes as he discussed Colorado quarterback Bernard Jackson.

"Another running quarterback," said Birdine, who has only one sack and longs to face a statuesque, drop-back passer. Of the Sooners' seven games, including Saturday's game with Colorado, they've faced only two quarterbacks who weren't a significant threat to run the ball.

"He's always been a great athlete," said OU defensive ends coach Chris Wilson, who was at Colorado when Jackson was recruited. "We were trying to devise different ways to get him on the field, if not returning punts, putting him at wide receiver.

"Finally, in this new system, he's done an exceptional job as their quarterback."

Jackson, who did not start and had only one rush in Colorado's first game, leads the team in carries with 93. Running back Hugh Charles has 90 attempts.

• Buffs' bowl: Birdine said he expects Colorado to be excited about the opportunity to play the Sooners on Saturday.

"This is, in essence, their bowl game, playing Oklahoma," Birdine said. "They're going to be firing on all guns. I'm actually a little nervous to play these dudes. They're gonna be amped up. And down the stretch, this might be one of our toughest games."

By Scott Wright