The Houston Texans have suffered a blow after it was confirmed J.J. Watt has sustained a fresh back problem and has been placed on injured reserve.
Watt underwent back surgery in July to repair a herniated disk and missed training camp and most of Houston's preseason schedule.
And the Texans, who lost in NFL for the first time this season in last Thursday's 27-0 beating at the hands of the New England Patriots, have confirmed the defensive end has been placed on injured reserve.
Watt played most of last season with torn torso and groin muscles and the herniated disk.
He has made eight tackles and recorded one-and-a-half sacks so far this season.
Antonio Smith, who was with the Texans from 2009-13 and a Pro Bowler in 2011, has been signed to the Texans' roster as cover for Watt.
Houston will aim to bounce back from the defeat against the Patriots when they take on the Tennessee Titans on Sunday.