The person spoke to The Associated Press on Tuesday night on condition of anonymity because the team hasn't confirmed the injury.
Watt missed training camp and Houston's four preseason games after surgery in July to repair a herniated disk in his back. He started each of the team's three regular-season games and got hurt again Thursday against the
It's unclear if the injury will require surgery, but the person familiar with his condition told the AP he could be placed on injured reserve as early as Wednesday.
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 he was just getting a day off.
It's a major blow for Houston, which selected Watt with the 11th overall pick in the 2011 draft. Watt has played 83 consecutive games for the Texans despite various injuries, including torn core muscles and a broken hand last season.
This was a tough offseason for Watt, who had surgery in January to repair five torn core muscles before going under the knife again in July to repair his back. There was a time after his surgery in January where he wondered about his future in the
"After the first surgery there were some days there where I really questioned whether or not I'd ever be able to play again," he said earlier this month. "Just some of the stuff we were dealing with from a rehab standpoint, just the way that the recovery was going early on there was a very low point there and it was tough."
Watt, who led the NFL with 17 1/2 sacks last season, has 1 1/2 sacks this season to give him 76 for his career .
The 27-year-old is a three-time Defensive Player of the Year and a four-time Pro Bowler. He's been a force since entering the league not only because of his pass-rushing prowess, but also because of his uncanny ability to swat down passes. He has 45 passes defended in his six-year career . He has forced 15 fumbles and recovered 13.