Mets right hand Robert Stock surgery has been recommended to correct thoracic outlet syndrome, Stock told reporters (including Jon Heyman of the New York Post) this morning. Heyman added that Stock indicated that he is suffering from arterial TOS, and that he may be able to perform before the end of the year. Stock was in camp with the Mets on a non-draft invitation but now faces an extended absence.
Stock, 36, has appeared in parts of five MLB seasons so far in his career. A second-round pick by the Cardinals back in 2009, he made a strong impression with the Padres in 2018, his first big league season. He posted a 2.50 ERA in 39 2/3 innings of work that year, but unfortunately struggled at the big league level since then. In 35 2/3 major league frames since, Stock sports a 7.57 ERA with almost as many walks (31) as strikeouts (39). The stock did not appear in the majors from 2022-2024, instead bouncing between the KBO, the minor leagues, and the independent leagues in the United States and Mexico. In 2025, he returned to baseball associated with the Red Sox. While making just two brief appearances in the majors, he pitched well at Triple-A Worcester with a 3.92 ERA in 85 innings as a swing man.
That led Stock to sign a minor league deal with the Mets through 2026, and he saw it as a flexible depth option for the club’s starting pitching staff. He has pitched well so far this spring, including a strong three-inning appearance against the Marlins while preparing to pitch for Team Israel in the World Baseball Classic. Unfortunately, that outing ended with him reporting discomfort in his shoulder. That led to an MRI which eventually revealed that he was suffering from TOS. A certain type of TOS Stock suffers from arterial TOS, a rare form of this disease. Although baseball fans have become more familiar with TOS in recent years, they may be more familiar with neurogenic TOS (a type of disease that players have). Stephen Strasburg again Chris Archer suffered) and venous TOS, Phillies star Zack Wheeler he is currently working on his return after disappearing late last year due to this disease.
Arterial TOS is less common than the other two variants, and its effects on baseball players are much less understood; A 2024 study published in the American Journal of Sports Medicine (link via NIH.gov) that looked at all 52 players who underwent TOS surgery between 2010 and 2017 noted that one of those 52 players had TOS. An article from Anthony Castrovince of MLB.com last month notes that arterial TOS can cause a cold sensation in the hand or even numbness in the finger. Castrovince’s article notes that a return to playing timeline of between nine and ten months is common for pitchers who undergo surgery to correct TOS, though that may depend on the severity and type of TOS the player is dealing with. Stock’s hopes for his timeline are more optimistic than that, as even a September return would be just a six-month turnaround.
Whether or not Stock is able to get him back on the mound this year, the Mets are ill-equipped to handle losing him as a depth piece. Justin Hagenman, Christian Scottagain Jonathan Pintaro all the deep rotation options are already on the 40-man roster, and that’s before the top prospects are considered. Jonah Tong. As for the bullpen, the Mets have a deep group of non-roster invitees headlined Craig Kimbrel, Adbert Alzolayagain Kevin Herget among others.
