Deshaun Watson suffered a torn ACL during practice on Thursday, an on-site test confirmed.
Watson will undergo an MRI for what was a non-contact injury to further diagnose the extent of the injury. Watson also suffered a torn ACL in his freshman season at Clemson.
Watson has been one of the NFL's best quarterbacks since becoming the Texans' starting quarterback.
The NFL named Watson AFC Offensive Player of the Month for October.
Tom Savage will start for the Texans moving forward.