Miller took a shot to his left leg during the Texans' opening possession of the game, and he appeared to be in immediate pain.
Trainers tended to the veteran back for a few minutes before the cart was needed to remove him from the field.
Miller has been the Texans' leading rusher for the past three seasons. He racked up 973 yards and five touchdowns on 210 carries in 2018.
Houston acquired additional backfield depth by trading for Duke Johnson on Aug. 8. If Miller misses time, the former Cleveland Browns standout would likely move into the team's starting role.