Pablo Sandoval will undergo surgery in Palo Alto on Friday to remove the fractured hamate bone in his left hand, manager Bruce Bochy said. Bochy said Sandoval will be out four to six weeks. Last year, he needed the entire six weeks and then a few days, but head athletic trainer Dave Groeschner said there is some hope he can return sooner now because this time it's not his throwing hand. "Tough news for us and Pablo," Bochy said. "I feel for him, particularly the way he has been playing and swinging the bat. … You just don't replace a bat like Pablo's. He was on the All-Star team last year. There are few guys in Major League Baseball who can do the things he can do with the bat." The Giants recalled left-hand-hitting Conor Gillaspie from Triple-A Fresno. He will start at third base today and Bochy plans to play him most every day.