Top sirloin is a cut of meat from the primal loin, subprimal sirloin, of a beef carcass. Top sirloin steaks differ from sirloin steaks in that the bone and the tenderloin and bottom round muscles have been removed; the remaining major muscles are the gluteus medius and biceps femoris (top sirloin cap steak). A baseball cut steak is the upper part of a top sirloin steak. It is a rounded piece of meat at least two inches thick. The meat fills out slightly as it cooks, which enhances its ball-like appearance.