J.J. Watt undergoes back surgery but expected to play in opener

Houston Texans defensive end J.J. Watthas had back surgery but is still expected to be ready to play when the regular season begins, a league source confirmed Thursday to ESPN NFL Insider Adam Schefter.

Watt will open training camp on the physically-unable-to-perform list and miss the preseason but is expected to be ready for the regular-season opener, the source said.

It's the second major surgery in six months for Watt, who had been rehabbing from a January procedure in which five fully or partially torn core-area muscles were repaired: three adductors and two abdominal muscles.

The Houston Chronicle previously reported Watt's back surgery.

Although Watt never missed a game, he suffered several injuries last season. He also played through a broken hand last season and a herniated disk.

Watt has not missed a game since being drafted in the first round in 2011. Even with all that turmoil, Watt won his third defensive player of the year award for his 17.5-sack 2015 season.

Information from ESPN's Tania Ganguli was used in this report.