Gray, an unrestricted free agent, was Jacksonville's backup last season and threw for 302 yards and four touchdowns in a meaningless regular-season finale against Houston. He will be the Texans' No. 3 quarterback behind Schaub and Sage Rosenfels.
Entering last season, Gray was the third quarterback in Jacksonville until the team released Byron Leftwich before the opener. Gray spent the rest of the year as the backup to David Garrard, starting four of the eight games he played and finishing with career highs in yards passing (986), passer rating (85.6) and touchdowns (10).
Gray appeared in 11 games over four seasons with the Jaguars.