Yes. I commonly cook prepared ribs still frozen using this method. When I buy a package of three racks of ribs, I will cook one fresh and trim, season, and foil wrap the others before cooking. They are good in the freezer for 3-4 months. If cooking frozen prepared ribs, it will add about 30 minutes to the cooking time. Determine when the ribs are fully cooked by the internal temperature of greater than 185° and the ends of the ribs showing.