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Though his results aligned with his magnificent season, Ryan Pressly felt awkward throughout his final two relief outings. He struck out three across the two scoreless innings but still maintained something was awry inside his right knee.

After watching the film of his outing against the Tigers on Tuesday, Pressly saw the problem.

"Come to find out, I was striding half a foot shorter than what I normally do," Pressly said Saturday. "I told (head trainer Jeremiah Randall) that something's not right and we went and had it looked at.

"It confirmed our suspicion of why it wasn't cooperating with us. We thought we had turned a corner by now but we still hadn't."

Pressly underwent arthroscopic surgery on Friday that will sideline him four to six weeks. His problems stem from a comebacker that caromed off his right knee on July 18. An MRI shortly afterward showed no damage that warranted surgery but one this week showed a new "small issue."

Pressly declined to reveal the exact nature of his operation.

The Astros are optimistic their All-Star setup man will return in time for the postseason, but general manager Jeff Luhnow acknowledged earlier this week there is a possibility Pressly could be unavailable for the American League Division Series. Six weeks from Pressly's surgery date is Oct. 4 — game one of the ALDS.

"We've got a plan to get back hopefully before the season ends, at least that's how I'm going to push myself and we'll go from there," Pressly said.

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