NEW YORK -- Starting pitcher Steven Matz has been diagnosed with irritation of the ulnar nerve in his left elbow, the Mets announced on Monday, and he will undergo surgery "to reposition the nerve and eliminate the irritation." The procedure has not yet been scheduled.
Matz, who underwent an MRI and CT scan on Monday, has struggled mightily this season since returning from left elbow issues that kept him out until June. The 26-year-old went 2-7 with a 6.08 ERA in 13 starts. His last time out on Thursday, the Yankees knocked him around, scoring seven runs (six earned) in 3 1/3 innings. Regardless, Matz refused to use the injury as an excuse while addressing reporters on Monday after the Mets' 3-2 extra-innings loss to the D-backs.
"I don't want to speculate and use it as an excuse because I was doing everything to get out there and pitch," Matz said. "To say that this was affecting me on the mound, I don't know."
When Matz received an MRI earlier in the year, the results did not show the nerve irritation. But Matz never experienced numbness in his fingers, a typical symptom of the irritation, and nerve tests had not been completed prior to Monday, which is why it was not diagnosed until then. Before that, he was being treated for inflammation.
The irritation made it difficult to work in between starts, the left-hander said, adding that it's something he has felt since Spring Training but never escalated. It's the latest setback in a long line of injuries for Matz, who has spent time on the disabled list during his first three Major League seasons and underwent Tommy John surgery as a prospect.

"It's tough," Matz said. "But I talked to some guys who have had this procedure done before, and they came back feeling good and it solved their problems. I'm happy that there's an answer to it."
Teammates Erik Goeddel and Jacob deGrom have each undergone the procedure. deGrom told him it was a "really easy recover and a really easy rehab," with little-to-no lingering effects, leaving Matz optimistic for 2018 and beyond.
When Matz first came off the DL on June 10, he pitched to a 2.12 ERA in his first five starts of the season. He has since regressed, as evidenced by his 0-6 record and 10.19 ERA over his last eight starts.
The Mets' rotation has been hit hard by injuries all year, as the club has needed 12 pitchers to start over the course of the season. Tommy Milone is expected to start on Tuesday in place of Matz.
Milone hasn't pitched since May, when he made three starts for the Mets before going on the DL with a left knee sprain. The 30-year-old left-hander went 0-2 with a 10.50 ERA in those three outings.
"You can never have enough [starting pitching]," Mets manager Terry Collins said when announcing Matz was headed to the DL before Monday's game. "This just tells you that anything can happen in any given time. There are no guarantees."