Jorge Lorenzo, the man many expect to give World Champion Valentino Rossi the biggest fight in this year's MotoGP World Championship, suffered a pre-season setback yesterday when he crashed his motocross bike and suffered a broken hand and a dislocated thumb.Lorenzo, Rossi's teammate on the Fiat Yamaha team and the runner-up in last year's title chase, underwent surgery on his right hand at the Capio Hospital General de Catalunya yesterday. He will miss the next test in Sepang, Malaysia, but is expected back for the final pre-season test in Qatar in March, according to Yamaha.According to a release issued by the team, Lorenzo crashed in a slow corner, doing approximately 20 mph. Doctors found that Lorenzo had suffered a fracture at the base of the first metacarpal and a displaced thumb. Dr. Augusto J. Casanovas made "an open reduction and osteosynthesis with a small titanium plate."Lorenzo will require hand protection for four to six weeks, according to Yamaha. The Spaniard was expected to leave the hospital this morning and will return to his home in Barcelona to recuperate.