Doctors will move the ulnar nerve, which had been causing intermittent elbow discomfort as well as finger numbness.
DeGrom expects a three-month recovery time from the procedure and to be ready for spring training. He consulted with Hall of Famer John Smoltz, who underwent the same procedure during his playing career.
The Mets will have four core members of their starting rotation trying to work back from surgeries during spring training.
Matt Harvey underwent surgery in July to remove a rib and relieve thoracic outlet syndrome. Steven Matz, currently sidelined with a shoulder impingement, is due to have a bone spur removed from his pitching elbow after the season. Zack Wheeler still is working back from complications from Tommy John surgery, which was performed in March 2015.
DeGrom, 28, went 7-8 with a 3.04 ERA in 24 starts for the Mets this season. He last appeared on Sept. 1.
Matz, who has been sidelined since Aug. 14, is due to rejoin the Mets on Wednesday. He will throw a bullpen session for team staff.
Matz is a consideration for Friday's start against the Philadelphia Phillies at Citi Field. However, manager Terry Collins indicated that Matz must first demonstrate his readiness by showing better sharpness with his secondary pitches than during his last bullpen session at the team's complex in Port St. Lucie, Florida.
Collins also openly questioned the wisdom of starting Matz if he will be capped at 50 pitches anyway.
Gabriel Ynoa is the alternate to start on Friday if the Mets do not use Matz.