Barreto left Thursday's game with Double-A Midland after fouling a ball off his leg in the first inning.
After a slow start to the season, the 20-year-old Barreto put together an eight-game hitting streak to end April, with six multi-hit games over that span. He added his third homer with the affiliate last week and two more stolen bases to give him seven in 11 attempts. The team has yet to elaborate on the exact nature or severity of this setback.