The good news for Pablo Sandoval and the Giants is that humans have only two hamate bones, and both are removable. The bad news: Sandoval now has fractured both of them.

The All-Star third baseman will have surgery on his fractured left hamate bone Friday, nearly a year to the day after he had the same procedure on his right wrist. Sandoval was put on the 15-day disabled list and is expected to miss four to six weeks.

He had his right hamate bone removed last May 3 and missed 41 games. The Giants are hopeful that the rehab process will move more quickly this time since the surgery is on Sandoval's non-throwing hand.

Conor Gillaspie was called up from Triple-A Fresno and started at third base in Thursday's 3-2 loss to the Miami Marlins at AT&T Park. Manager Bruce Bochy said he will give Gillaspie a chance to "take the (everyday) job and run with it" but acknowledged there is no easy way to overcome the loss of Sandoval.

"You just don't replace a bat like Pablo's," Bochy said. "There are very few guys in the majors that can do what he can do with the bat."

The Giants turned to a familiar saving grace when Sandoval had surgery last season. The pitching staff had a 2.99 ERA in his absence, allowing the Giants to go 25-16 as their most dangerous hitter recovered from surgery.

Ryan Vogelsong did his best to replicate that stretch Thursday, but the slumping lineup and error-prone defense couldn't keep the Giants from getting

swept for the first time since a season-opening series against the Arizona Diamondbacks.

The Giants scored five runs in this series. They lost all three games by one run, just as they did in Arizona.

"Hopefully this is kind of a wake-up call," first baseman Brandon Belt said. "We've got to raise the intensity, especially with Pablo out."

Vogelsong showed his trademark intensity through seven innings, giving up just one earned run despite allowing eight hits and walking four. The Marlins' other run came after another blunder by shortstop Brandon Crawford, who entered the season with a stellar defensive reputation but has six errors in 22 starts.