DALLAS -- Losing middle linebacker Ryan Reynolds didn't just rip one of the primary playmakers out of Oklahoma's defense.
It also opened the gates for a late Texas rushing boon and a run of late Sooner penalties after the junior middle linebacker was lost with a season-ending torn anterior cruciate ligament early in the third quarter.
Reynolds appeared to try to continue for several snaps before hobbling off the field. He limped to the sidelines and returned before the end of the game with the leg immobilized.
The shell-shocked Sooners never recovered as Texas charged to a 45-35 victory. After Reynolds' injury, the Longhorns erupted on a 25-3 run to finish off the upset.
"Any time anybody gets injured it will affect your defense or your offense," Oklahoma coach Bob Stoops said. "Ryan has been a major force and is a leader. It impacted us."
The injury affected how Stoops called plays late in the game. The Sooners' unsuccessful fake punt late in the third quarter was called to help give his team a boost of momentum after the injury, Stoops said.
Injuries are obviously a part of football. But they also have a big part of the overall success of a team. When the Sooners won the 2000 national championship, they sustained no major injuries that kept players out of the lineup for extended periods.
Texas players could discern a difference in Oklahoma's defense after Reynolds' departure. It was also no coincidence that Texas' rushing game started clicking as soon as he left the game.
"Ryan is the heart and soul of their defense," Texas quarterback Colt McCoy said. "When he went out, it didn't change anything for us. Their secondary backed off a little bit and that allowed us to use (Texas tailback) Chris [Ogbonnaya] to get a couple of big runs. It was a big momentum changer for us."
Reynolds was coming off the best game of his career. He graded out with a perfect score last week in the Sooners' victory over Baylor -- the first time that Oklahoma defensive coordinator Brent Venables had ever had one of his players notch that score.
"I don't know how it affected us out there," Venables said. "Obviously, you feel terrible for him having to go through that. He is a big part of what we do. He gets guys lined up for our checks and those kinds of things."
It represented the third serious knee injury that Reynolds had suffered in less than three years. He tore the left anterior ligament during the spring of 2006 and the lateral collateral ligament in the same knee last spring. And it will mean the third major rehabilitation that Reynolds will face as he tries to return to the lineup.
"This is his third ACL injury," Oklahoma defensive tackle Gerald McCoy said. "How many times does this have to happen to one guy? I feel bad for Ryan, more than for us. We'll be OK, but I'm more worried about Ryan."
Stoops will be left with several playing options for the rest of the season. Sophomore Brandon Crow was inserted into the lineup for most of the game after Reynolds' injury. But a more likely scenario might be that talented redshirt freshman Austin Box will be moved into the position.
"Losing a leader like him and the rock like he is, it's going to be tough for you," Oklahoma linebacker Travis Lewis said. "It gave another player a chance to make plays. We aren't making excuses, but it's tough losing a player like him."
Tim Griffin covers college football for ESPN.com. You may contact him at firstname.lastname@example.org.