(Jonathan Daniel/GETTY IMAGES)

“It’s a great start to the year for the Nationals,” DeRosa said. “A horrible start for me.”

DeRosa had felt a small twinge in his side for a day or two before Saturday night. During his outfield drills pregame, the pain suddenly worsened, but “I didn’t think nothing of it,” DeRosa said. “It bothered me, but it was nothing that scared me off.” But he went to take batting practice, he knew had been hurt.

Before signing with the Nationals, DeRosa overcame three surgeries on his left wrist, which limited him to 73 games over the past two years. DeRosa finally felt the strength return to his wrist this spring, and he punched up an on-base percentage over .500 in Florida.

But after his dispiriting start, DeRosa, 37, will likely be sidelined for several weeks, if not months, with an injury that requires significant rest.

“It’s been a frustrating start to the year for me,” DeRosa said. “It’s been a frustrating last whole 2 ½ years. I’ll deal with it. I’ll get back. We’re in first place, playing well.

“It’s frustrating because you work so hard. They say the older you get, the harder you have to work. I’ve come back from injuries. My body won’t give me a break.”

DeRosa becomes the sixth member of the projected 25-man currently on the disabled list, joining Chien-Ming Wang, Michael Morse, Ryan Zimmerman, Drew Storen and Brad Lidge. Rick Ankiel also began the year on the disabled list.

Moore has arrived at Dodger Stadium for batting practice. He will be available off the bench today.