WASHINGTON -- The Giants lost one of their few competent offensive performers Saturday as they announced that third baseman Pablo Sandoval will be sidelined from four to six weeks with a fractured hamate bone in his right hand.

Sandoval, 24, was leading the Giants in batting average (.313), on-base percentage (.374) and slugging percentage (.530). The switch-hitter was exempt from the team-wide slump gripping the Giants, who entered Saturday ranked 14th in the National League in scoring and 11th in hitting. Moreover, the slimmed-down Sandoval also had performed admirably on defense.

"This is a tough break for us," said manager Bruce Bochy, not intending a pun. "I feel for Pablo. He was really paying big dividends."

Sandoval maintained a philosophical attitude.

"Everything happens for a reason," he said. "I have to be positive. Everything's going to be quick -- four weeks, six weeks. I'll just try to get better as soon as possible."

Sandoval's move to the disabled list deepened the sense that this season could be as cursed as last year's was charmed for the Giants. Right fielder Cody Ross and closer Brian Wilson began the season on the DL. Center fielder Andres Torres, another key performer for the reigning World Series champions, hasn't played since April 9, when he strained his left Achilles tendon. Pitchers Barry Zito and Santiago Casilla remain shelved. And Thursday, utility man Mark DeRosa, who could have filled in for Sandoval, went on the 15-day disabled list with left wrist inflammation. DeRosa's not eligible to be activated until May 10.

"That's what makes losing a guy like Pablo even tougher," Bochy said, referring to DeRosa. "He would have softened that blow."

Bochy indicated that Miguel Tejada, who moved from shortstop to start at third base Saturday, will be Sandoval's primary replacement. Meanwhile, Mike Fontenot will receive the bulk of the playing time at shortstop. Sandoval's spot on the active roster will be filled by infielder Ryan Rohlinger, who hit .194 with four home runs and 14 RBIs in 20 games for Triple-A Fresno.

Giants general manager Brian Sabean affirmed that the club will not pursue trades to bolster the infield. He pointed out that the Giants should receive reinforcements during Sandoval's absence as DeRosa and Torres leave the DL.

Giants head athletic trainer Dave Groeschner said that Sandoval will undergo surgery "as soon as possible" to have the fractured portion of bone removed. Groeschner said that Sandoval likely will leave the team Sunday and visit a specialist Monday before having his surgical procedure performed by Dr. Don Sheridan of Phoenix.

Hamate bone fractures are common among ballplayers. Ken Griffey Jr., Troy Tulowitzki and Dustin Pedroia are among the most recognizable players who sustained this injury. Sandoval, who obviously did his homework, cited DeRosa, Mike Fontenot and Darren Ford as teammates who hurt themselves in similar fashion.

The cause of Sandoval's injury was unclear. Sandoval related that he could have hurt his hand while sliding headfirst stealing a base Thursday at Pittsburgh. Sandoval felt fine in Friday's series opener here, but Groeschner said that his hand felt "progressively worse" as the game elapsed.

Groeschner said that one potential complication in Sandoval's recovery is the fact that most hitters set the knob of their bat in the area where the incision will be made to remove the broken bone.

Groeschner expressed confidence that Sandoval, who lost approximately 40 pounds during the offseason, will succeed in maintaining his weight despite not playing for at least a month.

"He still wants to lose a few more pounds," Groeschner said, observing that Sandoval can continue to perform lower-body exercises. "This will be an opportunity for him to work on that part."