Bill O'Brien said Friday the defensive end would not play again in 2016.
Watt was placed on injured reserve Wednesday because of a back issue, and the team signed veteran Antonio Smith in a corresponding roster move. On Friday, O'Brien confirmed that Watt wouldn't be back with the Texans in late November or December.
Watt had played in all 16 games in each of his first five NFL regular seasons, and picked up the AP's Defensive Player of the Year Award in 2012, 2014 and 2015.
He tallied eight tackles, 1.5 sacks and a fumble recovery in three games this year.