Rafael Montero, a once touted pitching prospect in the Mets organization, was outrighted by the team on Friday and elected to become a free agent.
Montero, 28, underwent Tommy John surgery in the spring and missed the entire 2018 season.
The right-hander appeared in 58 games in four seasons with the Mets but failed to live up to expectations, going 6-16 with a 5.38 ERA in 192.1 innings pitched.
The Mets also outrighted Phillip Evans, who elected free agency, and righthand pitcher Jamie Callahan, who elected minor league free agency.
The Mets now have just 38 players on their 40-man roster.