Arian Foster has said that he suffered an Achilles injury during a "routine play" in the Houston Texans' defeat to the Miami Dolphins.
The 29-year-old told reporters: "Just a routine play. Trying to make a cut, gave out on me."
Head coach Bill O'Brien added: "I feel terrible for him. He's done a lot for us in the two years I've been here. I hate that part of the game."
Foster missed the first month of the season after sustaining a groin injury in pre-season.