SAN DIEGO -- Ryan Zimmerman was absent from the lineup again on Wednesday, but an MRI taken on the third baseman's right shoulder showed no structural damage. The lingering pain could, however, land Zimmerman on the DL if it does not subside soon.

Zimmerman said the soreness is due to inflammation in the AC joint in his shoulder, and that pain is still present when he swings. He did express relief in the news that no major injury showed up in the MRI results.

"I think the important thing is there's nothing wrong with my shoulder," Zimmerman said. "That was good news, obviously. I don't think anyone thought there was going to be anything wrong, but I have proof that there's nothing wrong. I guess it's good peace of mind. Now it's just a matter of figuring out the right combination to get it to relax, and once that's done, I'll be ready to go."

Zimmerman did receive a cortisone injection into the affected area over the weekend, but manager Davey Johnson said the shot could have missed the sore spot. Johnson also indicated that another similar treatment from team physician Wiemi Douoguih could be the solution.

"We'll rest him another day, and he'll take some swings tomorrow," Johnson said. "If he doesn't have any more relief tomorrow, he'll talk to Wiemi, and they'll treat him there."

Johnson also said a determination will be made about Zimmerman's spot on the roster at that time. Zimmerman has not played since Friday, and Johnson would not speculate on a potential replacement if Zimmerman goes on the DL.

Wang to make rehab start Saturday in Potomac

SAN DIEGO -- Chien-Ming Wang's recovery process will continue on Saturday, when the right-hander tests his sore hamstring in a rehab outing in Potomac.

Wang is expected to throw 65 pitches for the Class A affiliate, according to manager Davey Johnson, and will likely need about three more outings before returning to the big league club. Wang already had a successful outing in an extended spring game on Monday.

"He had a good outing already, no repercussions," Johnson said. "He's right on track. He'll need to get to where he's throwing right around 85 pitches. He's going to be at 65 next time out. I'd say at least three more [outings]."

Wang's spot in the rotation has been filled nicely by Ross Detwiler, who has compiled a 0.56 ERA in three starts. The decision about whether Wang would return to the rotation or the bullpen has yet to be made.