Mills completed eight of 13 attempts for 89 yards and was sacked twice in Friday's 20-12 preseason win over Pittsburgh.
Mills, who entered after starter C.J. Stroud played the first two series, was in the game for the most snaps of the four quarterbacks that saw action. He's locked in as the backup quarterback, although that was the case in 2023 when the Texans used Case Keenum to start games late in the season with Stroud unavailable.