Team doctor David Altchek will perform the procedure this week at the Hospital for Special Surgery in Manhattan, general manager Sandy Alderson said.
Edgin, 28, had sought a second opinion from Dr. James Andrews before committing to the elbow surgery, which will replace a stretched ligament and address a bone spur.
Before Edgin's fastball velocity sagged in a Grapefruit League appearance last Monday, raising concerns about his elbow, the Mets had struggled to identify a capable left-handed complement to him in the bullpen. Now, one of those relievers in camp -- Rule 5 pick Sean Gilmartin, Scott Rice, Dario Alvarez or Jack Leathersich -- will have to be the primary lefty trying to neutralize division rivals such as Freddie Freeman and Bryce Harper unless the Mets go outside the organization for help.
Gilmartin, Rice, Alvarez and Leathersich currently have a combined 11.77 Grapefruit League ERA.
Alderson said he is committed to having one left-hander in the bullpen.
Scouts have identified St. Louis Cardinals left-hander Sam Freeman and Washington Nationals left-hander Xavier Cedeno as two relievers in other camps who are out of options and unlikely to make their clubs' Opening Day rosters, making them logical trade candidates. The level of Mets interest in either is unknown.
"We'll continue to look at our internal options and we'll explore things externally as well," Alderson said.
Alderson had indicated Thursday that Edgin had the option of trying to rest and rehab for two to three weeks to see if the elbow would calm. The GM seemed to be advocating that position because he noted that if Edgin tried that "conservative" route and had the elbow issue flare up, he could commit to the Tommy John surgery by the end of the month and still not compromise 2016.
Edgin, though, expressed concern that a delay might affect his availability from the beginning of the 2016 season.
"It was the best decision for my future and my family," Edgin said in a statement. "The Mets stood behind me 100 percent. I'm disappointed, because we have a heck of a team. My mindset is to be ready to go on Opening Day 2016."
Alderson said Edgin's logic in deciding to have surgery now hinged even more on the fact that he had rested for much of the winter and still had the elbow issue flare up. Edgin dealt with similar issues last season. He missed two weeks beginning in late August. The GM said he had no quarrels with Edgin's decision.
"I don't think it was about the timing as much as it was about the probability that the conservative approach would work," Alderson said. "We're perfectly on board. Dr. Andrews gave a second opinion. This was Josh's decision, but certainly consistent with our thinking as well. It's not as if we're unhappy he's taking this approach."