They waived safety Jonathan Owens, whom they called up from the practice squad with injuries in the secondary.
The Texans also placed inside linebacker Dylan Cole on injured reserve. Cole tore the anterior cruciate ligament in his right knee Thursday night.
Heath, 26, has not played a game this season, but he appeared in 30 games with Houston over the past three seasons. He signed with the Texans on Nov. 11.
Mitchell, 24, has played two games this season. He has seen action on 14 offensive snaps and one on special teams.