The right-handed reliever was placed on the 15-day disabled list Friday and will undergo surgery to remove a bone spur and fragments of bone from the back of his right elbow on Tuesday. The Mets selected the contract of right-hander Fernando Nieve from Triple-A Buffalo.
"The bone spur that he had was creating irritation, and there's a reason, that's why he's been pitching not the way we're used to seeing J.J. throw," said general manager Omar Minaya. "The word that we have right now, he'll get back to throwing a baseball in six weeks. That could put him anywhere between 10 to 12 weeks."
Minaya compared the timetable to that of outfielder Angel Pagan, who came back after eight weeks. Minaya cautioned, however, that the timetable would be more conservative since the injury is more critical to Putz.
Putz, 32, is 1-4 with a 5.22 ERA and two saves in 29 appearances for the Mets this season. In his past three appearances, Putz allowed eight earned runs in 1 1/3 innings, and his ERA climbed from 3.21 to 5.22.
His role will be filled, primarily, by Bobby Parnell, who is 2-0 with a 2.08 ERA in 21 2/3 innings spanning 26 appearances. Parnell, 24, had been used as a seventh-inning reliever until Putz began to struggle.
"He gives us some relief there since J.J. just wasn't what he wanted to be or what we wanted," manager Jerry Manuel said. "[Putz] did a decent job, but it wasn't a lights-out eighth inning that we thought we would be getting. It's obvious that he was struggling physically. Since we were able to get by with that, we should be able to get by with Parnell in that role."
Manuel, though, wasn't willing to hand Parnell the role without a trial run, suggesting everyone in the bullpen will be leaned on more heavily.
"Everybody is going to get a shot. You've got to give everybody a shot now because you don't have the depth now that you had before," Manuel said. "You don't have anybody to rescue you like you had earlier. It's a matter of individuals, a team, everybody has to step up their responsibility."
Putz first began to feel discomfort in a bullpen session Wednesday, unbeknownst to Manuel, who used him Thursday in Pittsburgh for an inning, in which he allowed two runs on three hits.
"He has always been somewhat uncomfortable -- so that has always bothered him," Manuel said. "But it hasn't been an issue that he could damage any ligaments or tendons. It was something that was floating around that got in the way. Obviously he felt that it was getting to a point where it was getting more discomforting."
Nieve, 26, was 3-0 with a 3.70 ERA in four starts with Buffalo after he was claimed off waivers from Houston on March 14.
Sean Welsh is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.