A pitcher's stamina rating can based be explained as a hit points system. For each curve pitch (no drop/not fast) you throw, you lose one point of stamina. For each fastball or drop pitch you throw you lose 2 points of stamina. Once your remaining stamina hits 0, all you other values start decreasing with each pitch you throw. On the NES version of RBI, starting pitchers have a range of 40-54 points of stamina and relief pitchers have 12-16 points of stamina. The stamina ratings for Arcade pitchers are a bit more variant.