The Mets said Matz underwent an MRI and CT scan on Monday, as well as an injection for diagnostic purposes, and that surgery has been recommended to reposition the nerve and eliminate irritation.
"The symptoms weren't necessarily leading to the nerve," Matz said. "I got an MRI and an MRI doesn't show that from what I understand. So today they kind of used the last bullet and did the nerve test. Putting an injection in there and kind of numbing the nerve up and that kind of caused relief. That's why we are where we are."
Teammate Jacob deGrom underwent a similar procedure last September.
"It's tough, but I've talked to some guys who have had this procedure done before and they came back feeling good and it solved the problem. I'm happy there's an answer to it," Matz said. "I'm definitely really optimistic."
Matz, 26, had Tommy John surgery coming out of high school and more surgery to remove a bone spur last offseason
He began the season on the disabled list and has been struggling since his return, going 2-7 with a 6.08 ERA.
Matz's surgery is the latest setback for an injury-ravaged Mets pitching staff. New York began the season with World Series aspirations, but deGrom is the only starter remaining from the projected five-man rotation. Noah Syndergaard, Matt Harvey and Zack Wheeler are on the disabled list, and Matz will soon join them.
Information from The Associated Press was used in this report.