PITTSBURGH – Billy Wagner felt discomfort in his pitching elbow after throwing a simulated game Saturday and the New York Mets' closer won't come off the disabled list Monday as expected.

Wagner, sidelined with a strained left forearm, threw about 20 pitches in what was supposed to be his final step before rejoining the Mets on Monday, the first day he's eligible to come off the 15-day DL.

Initially, the report on Wagner was positive. New York manager Jerry Manuel, speaking to reporters about an hour after Wagner threw, said the left-hander was a little rusty but he had good velocity.

“The main concern is he's healthy,” Manuel said. “He should be ready to go Monday.”

Wagner later revealed that his elbow had flared up. He will return to New York on Sunday for further evaluation.

“I wouldn't say I am ready,” Wagner said. “Right now it is stiff and sore.”

The Mets have struggled to piece together a shaky bullpen without their All-Star closer, turning to Aaron Heilman, Pedro Feliciano and Scott Schoeneweis in save situations.

New York entered Saturday leading the NL East by one game over Philadelphia.

In other injury news, right fielder Ryan Church (post-concussion syndrome) played his second minor league rehab game Saturday. He went 0-for-3 with two strikeouts and an intentional walk as the designated hitter for the Gulf Coast League Mets.