Pablo Sandoval is expected to have surgery in Arizona on Tuesday to remove a fractured portion of the hamate bone in his right wrist, an injury that usually keeps a player out for four to six weeks.

Sandoval believes he hurt himself during a slide, but head trainer Dave Groeschner believes he did it swinging the bat. The hamate usually takes the brunt of a swing because that is where players rest the knobs of their bats.

Third baseman Ryan Rohlinger will be recalled from Triple-A Fresno, but manager Bruce Bochy said he is going to look at a regular pairing of Miguel Tejada at third base and Mike Fontenot at short, as it is for today’s game against Washington. Bochy will consider Emmanuel Burriss at shortstop for some games.

“It’s a tough blow for us,” Bochy said. “I feel for Pablo. We’ve talked many times about how hard he worked in the offseason to get in the condition he’s in, plus the way he is playing.”

Indeed, the Panda has been reborn since dropping close to 40 pounds over the winter. He has been playing above-average defense at third base and is one of only two Giants, along with Aaron Rowand, doing any hitting. Sandoval is hitting .313 with excellent on-base and slugging percentages of .374 and .530. He and Pat Burrell lead the Giants with five home runs apiece.

The timing of the injury is bad for another reason. His expected backup, Mark DeRosa, also is on the disabled list with wrist tendinits. Bochy said that having DeRosa would have “softened the blow.”

The hamate fracture is a common baseball injury. A’s fans might recall that Jose and Ozzie Canseco both had it at roughly the same time when they played in Oakland. The injury was spotted in an X-ray taken after last night’s game and confirmed with an MRI this morning.

Complications from this kind of surgery are rare, too. It’s a very simple procedure, but like any operation, time is required for the area to heal enough so it can take the pounding of contact with the bat knob. This would affect Sandoval more batting left-handed than right-handed.

I asked Groeschner if the medical staff will have to be vigilant about Sandoval maintaining his conditioning while playing.

“That’s one of the things we’ve talked about,” Groeschner said. “The one positive that he’s taking out of this is, he still wants to lose a few more pounds. He can work out his legs. He can still run. In fact, he’s inside workout out right now. He’s motivated to do that.”

Now, everyone waits to see how the rest of the struggling offense reacts to this blow. It’s a cliche to say some people will have to step up, but it’s time for some people to step up.

I tried to ask Sandoval about his injury before batting practice, and he referred all questions to Groeschner.