Oklahoma defensive tackle Charles Walker, who has missed more than a month from a concussion suffered on Oct. 1 vs. TCU, decided to end his career with the Sooners and prepare for the NFL draft, where he is rated as a one of the best defensive tackles on most mock draft boards.

Oklahoma still has two regular season games remaining — with the Big 12 title on the line — as well as a postseason bowl game.

This was Walker's third concussion. Walker, who has a 2-year-old daughter, decided turning the page to his professional career was the best decision for his family.

“Quitting on your teammates, that's hard to take as a coach,” OU defensive coordinator Mike Stoops told the Oklahoman. “Everything we stand for is our commitment to one another. For whatever reason, that wasn't there for him. He thought this was a better avenue. You'd have to ask him for those. From a coach's perspective, you don't see this happen very often. This is a unique situation. I don't know what the details are of it. You'd have to ask him. I'm sure he'll put out a release or tweet something.”

On Oct. 18, Walker tweeted: "I don't know where these rumors started about me not showing up to games or about me quitting. Do y'all really think Coach Stoops would allow anything like that on his team ... I don't need to acknowledge anything that's being said and don't care at all but I'll never leave my guys behind if I wasn't able to .... period .... but this season isn't about me it's about our team.”

Walker finished the season with seven tackles. For his career, he had 53 tackles and 6.5 sacks. Neville Gallimore, a redshirt freshman, has started four of the six games since Walker's injury.