"Anybody gets hurt, it's tough," Texans quarterback Deshaun Watson told reporters. "But he's one of the guys that brings a lot of energy and a lot of power to this team. It's tough to see him go off on the cart. I prayed for him. We'll be there for him every step of the way."
Cowboys defensive lineman Maliek Collins tackled Miller on the second offensive play of the game, hitting him just above his left knee. The 28-year-old tailback grabbed his left leg and was evaluated by team trainers.
The Texans' medical staff eventually carted Miller off the field.
"That was hard," Texans head coach Bill O'Brien said. "He's just an awesome guy. He's meant a lot to me personally and it's just a tough thing to see."
Miller has been the Texans' top running back since the 2016 campaign. In 14 games last season, he recorded 973 rushing yards and five touchdowns on 210 carries. He is entering the final year of his four-year contract.