1956 Pittsburgh Pirates Team Signed Baseball. While he wasn't able to lift the Pirates out of their doldrums, 21-year old Roberto Clemente proved he belonged in 1956. No signs of a sophomore slump occurred for Clemente as he hit .311 in 1956. This stellar Official National League (Giles) ball is signed by twenty-seven members of the squad in bright blue ballpoint. Bold blue ink signatures include: Pepper, Shepard, Johnny O'Brien, Kravitz, Cole, Roberts, Skinner, Hall, Walls, Freese, Arroyo, Thomas, McMahan, Groat, Law, King, Foiles, Virdon, Bragan (CH), Clemente, Swanson, Face, Friend, Kline, Eddie O'Brien, Long and one more. LOA from Beckett Authentication Services. Full LOA from PSA/DNA.