Oklahoma’s performance against TCU did more than saddle the Sooners with their first regular-season loss since 2002. It put them under the microscope.

The lens has been focused on the Sooners’ running game the last six days and will remain there when they face Tulsa at 11:30 a.m. today.

OU rushed for just 97 yards against the Horned Frogs. Adrian Peterson routinely struggled to get back to the line of scrimmage. Hit again and again, one of college football’s best running backs was forced to leave the game with an injury.

To make matters worse, the Sooner quarterbacks had little time to throw as well.

“If you’re going to allow people to penetrate and knock you back, you don’t have much of a chance,” OU coach Bob Stoops said. “I don’t care what your schemes are or what your great pass patterns are if the guys that you’re facing are hitting you or forcing the guy to throw or sacking him.”

Co-offensive coordinator Kevin Wilson coaches the offensive line and directs the Sooners’ running game. He believes his unit has to conquer even more after the opener.

“All we did is open a can of worms and show people: ‘Hey, bring it to Oklahoma,’” Wilson said.

TCU consistently stacked eight defenders near the line of scrimmage and made finding running lanes difficult. To make matters worse, OU also struggled to keep the Horned Frogs’ defensive line out of its backfield.

The performance called into question the offensive line’s physical toughness and whether it was physically and mentally prepared for the game.

“Sometimes we are going to come off with the wrong foot or play with poor fundamentals, but we can always play hard,” Wilson said, “and we did none of that Saturday.”

Statements like that caused the Sooners to do some soul-searching this week.

“Everyone has to take a long look in the mirror and see if they were really being honest with each other in the way they prepared for that game and they prepared for this season,” left tackle Davin Joseph said. “Obviously, what we were doing wasn’t right.”

The Sooners have spent this week taking a closer look at an offensive line that is trying to replace three-four year starters — Jammal Brown, Vince Carter and Wes Sims — from last year’s team.

The struggles would be easier to stomach if they could be attributed to young players. Most of the TCU troubles were at the center and guard spots, where seniors Chris Bush, Kelvin Chaisson and Chris Chester play. Bush and Chaisson have been starting for the last two seasons. Chester is a converted tight end.

Personnel changes up front are possible, but not likely. Freshmen tackles Branndon Braxton and George “Duke” Robinson could become factors, and freshman center Jon Cooper was coming on strong before an injury in practice this week. The unit’s depth took a hit when tackles Brandon Keith and Akim Millington left the team for good.