Montas is expected to miss 4-to-8 weeks with a broken rib, FOX Sports' Ken Rosenthal reports.
The young right-hander had surgery to remove a rib during the offseason, and the area has continued to be a problem even after the procedure. According to Rosenthal, the rib that Montas broke recently was showing signs of stress when he underwent the operation in February. He'll be sidelined for one-to-two months, which could drastically inhibit his chances of contributing at the major league level this season.