Leaning on Leahy

Cardinals breakout reliever is building the bridge back to Helsley

In 2024 the St. Louis Cardinals strength was undoubtedly their bullpen. The quartet of Fernandez, Romero, Kittredge, and Helsley was daunting for opposing offenses to try and muster any type of comeback against. Adding in contributions from names like Liberatore, King, Roycroft, and Kyle Leahy.

In 2025 the bullpen has been much more volatile, and Oli Marmol and his staff are doing their best to navigate the shaky ground and have seemingly formed a new bridge with the previously mentioned hold overs of Helsley and Romero and newcomer Phil Maton. Ryan Fernandez has struggled with command and consistency this season, so much so he was optioned to Triple A Memphis to give him a reprieve from the pressures of the big leagues so that he could regain the form he had demonstrated last season.

In has stepped Kyle Leahy to fill that void and rebuild that bridge from starter to Helsley that made the Cardinals bullpen so dynamic last season. So far in 2025, Leahy, has pitched 20.1 IP in 16 appearances and has pitched to a 1.33 ERA, a 2.98 xERA, a 3.71 FIP, a 3.48 xFIP, and his WOBA (weighted on base average) against is .173 which is 98th percentile in all of major league baseball. Inherited runners get stuck in cement when Leahy comes into a game with an exceptional 97.8 LOB% and his BABIP is .068. There may be some regression due in Leahy’s performance due to the high variance of luck he is experiencing. That’s not to diminish what he has accomplished so far this season. Make no mistake about it Leahy has been awesome and exactly what the Cardinals bullpen chain of command needed.

Taking a look at Kyle Leahy’s Savant page on MLB.com you can see how Leahy is performing against other pitchers across the league. His ability to limit hard contact and generate extension from the point of release allows his stuff to play up and its resulting in a lot of weak contact. Leahy’s sweeper is leading the way in his arsenal. No hitters have managed a hit off of it and has an xBA of .038 xSLG of .085 and xwOBA of .051.

If Kyle Leahy can continue pitching at this rate for a full season (unlikely but fingers crossed) and they can get a Ryan Fernandez return to form and Jojo can build on his high leverage appearance against the Mets. It’s not difficult to see how this bullpen could once again be a force to be reckoned with in the National League.

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