Grade 2 UCL injuries typically involve partial ligament tearing and frequently lead to Tommy John surgery. If surgery becomes necessary, Birdsong would likely miss the entire 2026 season and potentially part of 2027. A rehabilitation path could allow him to return later this year, though he is likely to be out for months regardless of the treatment choice.

“It’s certainly not best-case scenario, but hopefully we get best-case scenario of the unfortunate circumstances,” said manager Tony Vitello.

Birdsong felt discomfort during a relief outing against the Cleveland Guardians on Tuesday after throwing a curveball, describing the sensation as a “pop” and “rip.” Before the injury, his final spring appearance showed improvement, demonstrated by a scoreless inning with velocities reaching 99 mph. Over three spring outings, however, he allowed eight runs while working to refine his command and introduce a new cutter.

Birdsong had a 4.80 ERA across 21 appearances in 2025, including 10 starts, while walking 37 batters in 65⅔ innings. He also holds a 4.77 career ERA and 4.81 FIP in the majors, though he opened last season strongly with a 2.37 ERA over his first 14 outings.

The injury weakens the Giants’ pitching depth behind starters Logan Webb, Robbie Ray, Adrian Houser, Tyler Mahle, and Landen Roupp. Younger options such as Carson Whisenhunt, Trevor McDonald, Blade Tidwell, and Carson Seymour may now be required to provide additional depth, while non-roster pitcher Caleb Kilian could also become a consideration if injuries further impact the staff.