For the last two seasons, Adrian Peterson has been the face of Oklahoma football. He was the guy on the highlight clips and the sound bites.

But thanks to the broken collarbone he suffered last week, he’ll be wearing a sling at 6 tonight when No. 20 OU (4-2, 1-1 Big 12) faces Colorado (1-6, 1-1) at Owen Field.

Thus far, it ranks as the most important thing to happen to OU this season and has put the Sooners at another crossroads. Losing the Heisman Trophy candidate will either kick them down the road toward mediocrity or serve as motivation to launch them toward the second-half run they still believe they’re poised to make.

“I know I’m excited to go out there and see what we’ll do,” quarterback Paul Thompson said. “I know I’m not worried about much personally. Other guys might be. When I heard the news I was upset and shocked at the same time, but I was like: ‘Let’s go, we’ve got half a season over, let’s see what we’ve got this next time.’ I’m ready to go.”

Where some see doom, others see opportunity. How well the opportunity is embraced will be a big factor in OU overcoming its latest setback.

The Sooners will turn to running backs Allen Patrick and Jacob Gutierrez. Both shined last year when Peterson missed the better part of four games with an ankle injury.

Offensive coordinator Kevin Wilson doesn’t expect massive changes to the offensive. But the Sooners will tailor their play-calling to Patrick’s and Gutierrez’s strengths.

Patrick, who has rushed for 62 yards on 18 carries this season, figures to take more snaps out of I-formation or one-back sets. Gutierrez has excelled in spread formations and will be involved heavily in passing situations.

“We’ll probably do some things in the shotgun, we’ll probably do some things under center,” Wilson said. “We’ll try to keep our mix.”

The Sooners need to. Overhauling the offense is virtually impossible halfway through the season.

The words “step” and “up” were thrown around the Switzer Center like candy on Halloween this week.

Offense, defense, special teams, you name it, the Sooners talked about how better play in every phase would counter the loss of Peterson.

“We know the things we need to do,” Gutierrez said. “Having a player like Adrian was a luxury. A player like that — you put him out there and just ride him. The whole team knows that no one person is going to take his spot. We all know we need to contribute more and play better as a unit.”

Colorado has only won one game, but last week’s 30-6 romp over Texas Tech was evidence it can’t be taken lightly. There’s little chance of OU doing that considering its position.

Sooner coach Bob Stoops has no doubt what he believes will happen. He spoke about an improving defense and the way Thompson and receivers Malcolm Kelly, Juaquin Iglesias and Manuel Johnson have become big-play threats.