(Reuters) - Houston Texans All-Pro defensive end J.J. Watt underwent back surgery on Thursday and is expected to miss the remainder of the season, the NFL reported on its website. Watt was placed on the injured reserve on Wednesday after re-injuring his back during last week's loss to New England.

"I haven't missed a game since my sophomore year of high school," Watt tweeted. "This won't be fun, but it is necessary in order for me to return to 100 percent and play at the level that I am capable of playing at."

Watt, a three-time NFL Defensive Player of the Year, entered the season on the mend.

He missed the entire pre-season after having surgery to repair a herniated disk in late July, made it back for the season opener and played in his team's first three games. Watt led the NFL with 17.5 sacks last season.

(Writing by Jahmal Corner in Los Angeles; Editing by John O'Brien)