Star defensive end Kayvon Thibodeaux leaves Oregon Ducks' season opener after first half

Thibodeaux's strip sack sets up Oregon TD (0:39)

Oregon gets on the board thanks to a great defensive play from Kayvon Thibodeaux and a CJ Verdell touchdown. (0:39)

Oregon star defensive end Kayvon Thibodeaux was knocked out of Saturday's win over Fresno State with a left ankle injury.

Ducks coach Mario Cristobal sounded hopeful about the severity of the injury in his postgame availability, saying that it was an ankle sprain and that X-rays came back negative. Oregon will meet No. 4 Ohio State next Saturday in Columbus, Ohio.

"We're very optimistic it's nothing serious," Cristobal said.

ESPN NFL draft expert Mel Kiper Jr. listed Thibodeaux, a junior, as his No. 1 prospect, after he finished with 12 quarterback pressures last season.

Thibodeaux, an All-American last season, had a sack and a forced fumble in the first half against the Bulldogs, but did not come out with the rest of the team to begin the second half. When he returned to the sideline, he was wearing street clothes and a walking boot.

Fresno State battled on the road, but Oregon eventually outlasted the visitors 31-24. As players met on the field for postgame greetings, Thibodeaux walked into the locker room on his own.