The Mets, who entered Monday leading the NL East by a half-game over Philadelphia, said Delgado has a bone spur and a torn labrum in his hip. Team spokesman Jay Horwitz said no timetable for Delgado's return will be decided until after the operation.
"The way Carlos was responding to all the things he was trying -- and it wasn't getting any better -- I wasn't too optimistic about it," Mets manager Jerry Manuel said. "What we have to do now is try and find out how we're going to continue to play good baseball without Carlos Delgado."
In other news, reserve infielder Alex Cora was placed on the 15-day disabled list with a torn ligament in his right thumb. Ramon Martinez was called up from Triple-A Buffalo to play shortstop in place of Jose Reyes, who missed his fifth straight start with stiffness in his right calf.
"The doctor said give Reyes one more day," Manuel said.
Delgado was put on the 15-day disabled list Saturday. The two-time All-Star first baseman is hitting .298 with four home runs and 23 RBIs in 26 games. His 473 home runs are two shy of Stan Musial and Willie Stargell for 28th place on the career list.
"I feel for Carlos because I know how badly he wants to be out there, but we can't worry about how much we'll miss him," third baseman David Wright said. "We've got to look forward and go with the guys we've got and take care of our business. We can't sit back and feel sorry for ourselves because we're missing one of our main guys. Everybody has to do a little bit more. The guys that are in there every day have to pick up the slack."
The 36-year-old Delgado enjoyed a resurgence last year, batting .271 with 38 home runs and 115 RBIs. But an examination Monday in New York confirmed what the Mets feared -- their cleanup hitter will be out for a while.
Delgado hit .423 (11 for 26) with three doubles, a homer and seven RBIs in the seven games before he left the lineup, all won by the Mets.
"He's a big part of this ballclub and a big part of this lineup, so we're going to miss him," center fielder and No. 3 hitter Carlos Beltran said. "But we still have to go out and play baseball, do the best we can with what we've got and keep ourselves in good shape [in the standings] so that he can help us when he comes back."
"We made a real good run last year with people who were not in their natural positions," Manuel said. "I mean, we played two third basemen in the outfield, and they responded very well."
"When somebody goes down, whether it's him or anybody else, you have to have guys who can step in and try to hold down the fort until he gets back," Sheffield said. "Delgado's a power hitter and he can hit the ball out of any ballpark, so obviously we're going to miss his power and we're going to have to score runs any way we can. Hopefully, we'll get him back sooner than later."
Cora was injured on a headfirst slide Sunday night at San Francisco. He wasn't able to throw Monday, and X-rays showed the torn ligament.
Martinez's contract was purchased from Buffalo, and he batted seventh against the Dodgers. Left fielder Angel Pagan moved up to Reyes' leadoff spot, and second baseman Luis Castillo was in the No. 2 hole.