Clowney has played in only four games this season. He missed six games after undergoing surgery to repair a torn meniscus in Houston's season-opening win over the Washington Redskins and returned for the team's Oct. 26 win over the Tennessee Titans.
Clowney then sat out Houston's Nov. 2 loss to the Philadelphia Eagles due to both his knee and an illness. He has played the past two games, including a Nov. 23 loss to the Bengals in which he recorded a season-high three tackles.
Clowney did not practice Wednesday and said his chances of playing in Sunday's game against the Titans in Houson are "slim right now." He is expected to test out his knee before the game, according to the report.
"A lot of pain right now, just been bothering me off and on the whole season," Clowney said. "Something I've got to push through, but when the swelling comes up, it's a little setback."
The Texans selected Clowney out of South Carolina with the No. 1 overall pick in this year's draft. Houston is 5-6 and in second place in the AFC South.
- Chris Johnson