Early Monday morning after a tough loss to Texas, Ryan Reynolds was in the film room.

He was also doing pushups on the sidelines during practice Monday while his teammates ran through drills.

This is in spite of the fact that Reynolds went down with a season-ending anterior cruciate ligament (ACL) injury to his right knee in the third quarter against Texas.

“He loves it,” said head coach Bob Stoops. “I picked him up off the ground and said ‘What are you doing’?”

Reynolds’ determination and love of football will be difficult for the Sooners to replace.

“He’s limping around, but [mentally] he’s still out there with us,” said redshirt freshman linebacker Travis Lewis. “That’s typical Ryan.”

Reynolds switched to the middle linebacker position during the offseason to fill the void left by Curtis Lofton, who departed for the NFL.

Reynolds is the only member of this year’s linebacker corps to have starting experience at the position.

Lewis redshirted last season, and junior Keenan Clayton has played safety the past two years.

Reynolds’ standout game this season came against Baylor, when he recorded 14 tackles and was given a 100 percent grade by defensive coordinator Brent Venables.

Venables said that is the first time in his 25-year career he has given a player a perfect grade.

Aside from bruising ball carriers, Reynolds has become a strong leader both vocally and by example.

“You can’t undervalue that,” Venables said. “It is big. [For] any team that goes through a similar situation, which everybody does to some degree, it’s really advantageous for you when you can have a guy that can actually be an asset for you in that regard.”

The Sooners’ main goal during practice this week will be to find someone who can at least attempt to fill Reynolds’ shoes.

The coaching staff would not give a definitive answer about who will start this weekend against Kansas, but redshirt freshman linebacker Austin Box is the likely candidate.

Box is competing with sophomore Brandon Crow — who took Reynolds’ place against Texas — and junior Mike Balogun. Box was the only one made available to the media after Monday’s practice.

Box was expected to be the starting outside linebacker this season before having arthroscopic knee surgery to repair cartilage in his left knee. During his rehabilitation period, Lewis stepped into the starting lineup and looked impressive.

Box was a standout in high school, recording 71 tackles and three interceptions en route to being named defensive player of the year and all-state by The Oklahoman after hi senior season before being redshirted last season.

Box said he has no concerns about stepping into the starting lineup.

“At this point in time, all it comes down to is the mental work,” he said. “I don’t feel overwhelmed at all. It’s just an opportunity that I have to come in and step in and make some plays.”

Whoever steps into Reynolds spot will be expected to maintain a high level of play, but the entire defense will now to be forced to take on more leadership responsibilities.

“I mean, it’s just another challenge,” Lewis said. “I’ll help with the calls as much as I can and get myself lined up and play football.”