The Houston Texans won the team’s season opener against the Washington Redskins, but lost rookie linebacker Jadeveon Clowney to a knee injury.

ESPN noted that Clowney suffered the injury late in the second quarter.

Fans at NGR stadium collectively held their breath when Clowney limped off the field. He headed to the Texans locker room and did not return in the second half.

In his pro-NFL debut, the first overall pick in the 2014 draft had one tackle for a loss of nine yards, before exiting the game. Houston defeated Washington 17-6.

The outside linebacker has struggled with injuries throughout the preseason, but was ready to go on Sunday. His status for Week 2 though, is now uncertain.

FOX Sports reported that head coach Bill O’Brien was optimistic at his postgame press conference and said that the early prognosis on the 21-year-old’s knee is “good.”

Clowney played his college ball at the University of South Carolina where he recorded 24 sacks. In 2011, he was the SEC Freshman of the Year and was the SEC Defensive Player of the Year in 2012.