Sanmartin (elbow) underwent season-ending UCL surgery back on July 7, Mark Sheldon of MLB.com reports.
The initial hope was that Sanmartin would be able to return in 2023, but a more serious issue was discovered beyond the initial diagnosis of a stress reaction in his left elbow. It wasn't reported as Tommy John surgery specifically, but this will take Sanmartin out for the remainder of the season and could threaten his availability for spring training in 2024.