There is concern the injury will force Foster to miss the start of the regular season, according to a source.
Foster suffered the injury on a pass play Monday night and did not return to the field. Running back Alfred Blue took over some of Foster's first-team repetitions in his absence. Blue also left the field during that practice, but reportedly only did so for cramps.
Foster ranked sixth in the NFL last season with 1,246 rushing yards despite missing three games entirely due to injuries and parts of three others due to injuries. He missed two games last November after suffering a groin injury against the Philadelphia Eagles. He also missed the Texans' Week 3 contest against the New York Giants with a hamstring injury.