Houston put Watt on injured reserve Wednesday after he reinjured his back. Watt had surgery in late July on a herniated disk in his back and missed all of training camp and the preseason, but was back for Week 1 against the Chicago Bears.
ESPN previously reported that Watt had the surgery Thursday.
In three games this season, Watt had 1.5 sacks and a fumble recovery, though he rarely looked as explosive as he has in the past.
The three-time NFL Defensive Player of the Year will miss the first game of his six-year NFL career on Sunday against the Tennessee Titans.