The No. 1 overall pick limped to the Houston Texans locker room with a knee injury late in the second quarter of Sunday's season opener against the Washington Redskins. Clowney did not return in the team's 17-6 win.
"Looks like he's gonna be OK," Texans coach Bill O'Brien said after the game. "He may miss some time, he may not. We don't know yet."
NFL Media's Albert Breer later reported that Clowney suffered a sprained MCL and could be sidelined for awhile. Breer added that more tests would be conducted Monday.
Clowney had one tackle for a loss before exiting the game.
The "Around The League Podcast" is now available on iTunes! Click here to listen and subscribe.