"I am done," the three-star defensive tackle from Garland, Texas, told regional analyst Greg Powers.
Four months later and nothing has changed.
"I'm very solid on my commitment," he said this week. "I'm excited about going to OU."
Walker's Garland High School team is struggling to get wins this season, posting a 1-5 record entering Thursday's game with Lakeview.
"We've been struggling, but we've played some pretty good teams," Walker said. "Lakeview isn't as good as some of our other competition, so I think we've got a good chance to pick up another one."
Walker has recorded 20 tackles from the interior of the D-line and "has been playing very good," according to Garland head coach Jeff Jordan.
"I think I'm playing pretty good right now, but I'm not worried about stats," Walker said. "I'm just concentrating on helping us get some more wins."
Walker (6-1, 290) is rated the No. 45 defensive tackle in the nation.
He committed to the Sooners after attending a camp this past summer.
He chose OU over Mississippi, Arizona, Colorado, TCU and Mississippi State.