"I'm not optimistic that he'll pitch again this season," manager Jerry Manuel said, and later that day, his fears were confirmed.
The Mets announced late Tuesday that an MRI revealed new fraying and a slight tear to the ulnar collateral ligament in his elbow.
Though Putz will not undergo an additional procedure, he will not pitch again this year.
Earlier Tuesday, Putz, who is recovering from surgery to remove a bone spur from his right elbow, was scratched from his scheduled rehab start at Class A Brooklyn. That news came three days after Putz threw all of his pitches in a 19-pitch bullpen session, giving it a glowing report afterward.
Thereafter, the Mets established a schedule for a two-appearance rehab stint, which would have put Putz on track to rejoin the team early next week. But those plans have since changed.
The news was no better for Oliver Perez, who remained in New York to see a doctor regarding his balky right knee. Though Perez still may make his scheduled start Friday in Chicago, there are no guarantees.
Earlier this season, Perez spent more than two months on the disabled list with tendinitis in that same knee.
"I think it's been a factor all year long," Mets pitching coach Dan Warthen said. "We've never seen Oliver throw a ball over 91 or 92 [mph] at any time."
Perez, in the first season of a three-year, $36 million contract, is 3-4 with a 6.82 ERA.
Anthony DiComo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.