(Reuters) - San Francisco could be without All-Star third baseman Pablo Sandoval for an extended period after the Giants' second-leading hitter broke a bone in his left hand, the team said on Thursday. Sandoval, who missed 41 games last season with a similar injury in his right hand, fractured a bone in his wrist during Wednesday's game against the Miami Marlins and could be out for six weeks. He was placed on the 15-day disabled list. Sandoval is hitting .316, in 24 games this year for the Giants, who are 4-1/2 games out of first place in the National League West division. ...