The Mets have likely lost top starter Jacob deGrom for the season after the right-hander experienced pain in his elbow Friday.

GM Sandy Alderson said the pain is ulnar nerve-related and likely will require surgery. The Mets believe deGrom is experiencing something common for pitchers who have had Tommy John surgery: a buildup of scar tissue that presses on the nerve.

"It's unlikely he'll pitch again this season," Alderson said.