SACHSENRING, Germany - MotoGP champion Jorge Lorenzo has withdrawn from Sunday's German GP for more surgery on his left shoulder, damaged in a crash two weeks earlier.He crashed again on Friday (July 12) during practice for the 2013 German GP here.The Spanish Yamaha rider is second in the 2013 championship behind compatriot Dani Pedrosa of Honda after seven of 18 races. He riding quickest in Friday's afternoon practice but lost control at Turn 10 and landed heavily on the already damaged shoulder.BROKEN COLLARBONEMotoGP organisers said on their website: "He was taken to the mobile clinic where examinations indicated that the eight screws in his shoulder were intact but the titanium plate had been bent by the impact." The screws and plate were inserted two weeks earlier after Lorenzo broke a collarbone in practice for the Assen GP in the Netherlands. Despite that injury and surgery in Barcelona he flew back to the Netherlands, raced, and finished fifth.After this latest setback he's now in a race to be fit in time for the US MotoGP at Laguna Seca on July 21.Lorenzo said on the Yamaha website: "I've decided to go home and recover after today's crash. I prefer to focus on surgery to fix the bent plate."I will try to recover and be back as soon as possible."