SEATTLE -- Seattle Mariners left-hander Marco Gonzales will undergo nerve surgery and will miss the rest of the season.

Gonzales will have surgery Aug. 22 to decompress the anterior interosseous nerve in his left forearm. The 31-year-old hopes to recover by spring training.

"This comes after a lengthy process of trying to find answers," Gonzales said Sunday. "This gives me the best chance to move forward and get past this so it doesn't happen any further."

Gonzales was 4-1 with a 5.22 ERA in 10 starts. He hasn't pitched since May 28, when he felt discomfort in the forearm after throwing 5 2/3 innings against Pittsburgh. At the time, the Mariners thought Gonzales had a forearm strain.

"It became harder and harder to get loose each inning," Gonzales said. "I felt some achy soreness in my forearm, in the middle of it. Basically ever since then each time I go to throw a baseball I feel this aching, sore pain in the middle of my forearm."

Gonzales said throughout the summer that every time he went through a treatment plan and started throwing, pain remained and the underlying cause wasn't clear. He worked with specialists over the past few weeks in a process he described as "popping the hood" when the issue with the nerve was found.

He has a $12 million salary next year in the final season of a $30 million, four-year contract. The deal includes a $15 million team option for 2025 with no buyout.