Watt, who has won Defensive Player of the Year for the past two seasons, didn’t practice on Monday, but coach Bill O’Brien said then he was just getting a day off. Watt missed training camp and Houston’s four preseason games after surgery in July to repair a herniated disk in his back. He returned started each of the team’s three regular-season games and got hurt again Thursday against the Patriots.It’s unclear if the injury will require surgery. HOUSTON (AP) — A person familiar with J.J. Watt’s condition says he has re-injured his back and the Houston Texans expect him to be out until at least December, and possibly the entire season.The person spoke to The Associated Press on Thursday night on condition of anonymity because the team hasn’t confirmed the injury. NFL.com first reported the news.