PHILADELPHIA -- The tear in the stomach muscle of Ryan Zimmerman, repaired Tuesday by Dr. Bill Meyers, was less extensive than expected, leaving the Nationals fully expecting their star third baseman back by mid-June.

"The doctor told me, 'Six weeks until he's in the lineup.'" Washington general manager Mike Rizzo said. "It wasn't as invasive as it could have been for that type of surgery.

"[Zimmerman] is at the hotel here in town resting comfortably. He will be here [at Citizens Bank Park on Wednesday] to begin his rehab."

Zimmerman first felt discomfort during Spring Training, then did more damage to himself with a slide into second base the second week of the season. He hasn't played since April 9. A visit with Meyers here Friday confirmed the necessity of surgery to get Zimmerman back in the shortest amount of time.

"It started out very minor back in the beginning of March," said Dr. Wiemi Douoguih, the Nationals' medical director. "We shut him down ... [but when] he slid into second base during a game the first or second week of April, then it really got much worse after that.

"That's when we shut him down and put him on the [disabled list]."

In Zimmerman's absence, 13 starts at third base have been taken by utility man Jerry Hairston, but with Rick Ankiel taking a one-day break to nurse a hand he rolled in making a catch Monday night, Hairston was in center Tuesday and Brian Bixler at third as the Nationals opened a series with the Phillies.

"[Hairston] is a baseball player, pretty good anywhere," manager Jim Riggleman said. "I have always felt if a guy can play short, he can play center field.

"There are going to be some big people playing short in today's world, but most in a pinch if you needed them in center, they could fit in there. And Jerry's in that group."

Zimmerman will continue his rehab in Washington while the team continues on its three-city trip to Miami and Atlanta. In his absence, the Nats are 13th in the National League in RBIs and 15th in batting average.