HOUSTON (AP) — No. 1 overall pick Jadeveon Clowney had a setback with his surgically repaired right knee and said Thursday that his chances of playing for Houston at Tennessee on Sunday are slim.

Clowney has played just four games this season after being injured in Week 1. The outside linebacker, who had arthroscopic surgery Sept. 8, was in for about 50 plays last Sunday in his most significant action since his injury.

He experienced swelling in his knee after the game and hasn't practiced all week. On Thursday he acknowledged for the first time just how much his knee is hurting him.

"(I'm in) a lot of pain right now," Clowney said. "Just been bothering me off and on the whole season. It's something you've got to push through, but when the swelling came up it's a little setback."

Coach Bill O'Brien said the team will likely decide if he'll play right before the game Sunday.

Clowney missed six straight games before returning Oct. 26. He sat out the next week with an illness before playing the last two. He had three tackles, including one for a loss, in a loss to the Bengals on Sunday.

Clowney has been criticized by outsiders because he hasn't played very much this season. But he tries to brush off the negativity.

"It's all right," he said. "That's what people do is talk. I can't worry about what people say. ... I'm just trying to win games. If I can go, I'll go. If I can't, I can't."

Clowney never expected this injury to still be limiting him more than 2 1/2 months since his surgery.

"I'm kind of surprised," he said. "I thought it would have been over. I thought it would have been back to where it was by now. But some people react different to injuries, so I guess I reacted a little differently."

The Texans drafted Clowney after a three-year career at South Carolina in which he had 130 tackles, 24 sacks, 47 tackles for losses and 20 quarterback pressures. He also caused a school-record nine fumbles and deflected seven passes. The 21-year-old also set a South Carolina record with 13 sacks in 2012.

It was there that he gained a reputation as one of the hardest hitters in the Southeastern Conference, and he's frustrated that he hasn't yet been able to perform at that level in the NFL.

"It's very tough knowing my ability and how I can play but that my knee won't let me," he said. "That's the hard part about it that my knee keeps me from doing a lot of things I was doing before I got hurt. I'm just trying to get back to where I was before."

He has improved from the beginning of the week. Clowney was walking with a noticeable limp Monday but was moving around better Thursday.

"It's coming back along," he said. "It's just taking time right now."

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