9 Cardinals who took advantage of their runway in 2025

The Bullpen Reinforcements - Matt Svanson, Kyle Leahy, Riley O'Brien

When Steven Matz, Phil Maton, and Ryan Helsley were dealt at this year's trade deadline, the question of who would fill those high-leverage roles for the rest of this year and next year grew ever more important. JoJo Romero would become the de facto closer, but a "closer-by-committee" approach was far more likely. Three relievers have filled those holes quite nicely.

Matt Svanson, Kyle Leahy, and Riley O'Brien have used the 2025 season to establish themselves as high-leverage pitchers for the foreseeable future.

In 55 innings of relief for the Cardinals this year, Matt Svanson has a 2.13 ERA. He's struck out 61 batters, and he's walked only 19. His fastball consistently sits in the upper 90s, and he pairs it nicely with a sweeper that generates whiffs 27% of the time with an opponents' batting average of just .159 against it. Svanson has logged four holds this year, and he's grown quite comfortable with late inning appearances. After all, he did record 27 saves last year for the Springfield Cardinals.

Kyle Leahy has been with the major league team all year, and he's been Oliver Marmol's workhorse in relief. Leahy has thrown 81 innings this year, second most among relievers behind only Mike Vasil of the Chicago White Sox.

Leahy has a 3.33 ERA and a 3.14 FIP on the year. He's struck out 75 batters and walked only 27 thus far for a 2.78 K/BB ratio. Leahy has had his rough months this year, including a 4.40 ERA in June and a 6.48 ERA this month, but he's been reliable for Oli Marmol, and his role could grow even more next year if he assumes a spot in the rotation.

Riley O'Brien has always been a tantalizing prospect. Few relievers have as good stuff as he does. His issue, as is often the case with relievers who have a similar profile, is control. That's still a bit of a concern with O'Brien, but he's managed to pitch well in spite of those control issues.

O'Brien has a 2.08 ERA this year in 43.1 innings, and he's become a reliable late-game pitcher since the trade deadline. He struck out 13.09 batters in July, and he's fared well late in games and in high-leverage situations. He has a 9.28 K/9 rate to go along with a 2.49 FIP in such situations.

While the bullpen isn't often a place that a "rebuild" focuses on, the Cardinals need not be worried when looking at the future of relief for the organization, thanks to the growth of Matt Svanson, Kyle Leahy, and Riley O'Brien.