Starting today, I’ll be doing a series of columns about the St. Louis Cardinals and the players and pitchers that intrigue me. It’s a good way to look back to 2025 but also gaze ahead to 2026.
I plan to format these so they are easier and enjoyable to read. I’ll also try to provide some statistical stuff that you may not know about. Thank you!
Today: Pitcher Kyle Leahy.
The Question: Can the right-hander earn a spot in the team’s 2026 starting rotation?
Quick-Take Review of 2025: Including one “opener” at the start of a game, Leahy led NL relievers with 88 innings pitched last season. Leahy had an important role because of his stamina and durability.
In his 62 relief appearances last season, Leahy recorded at least four outs 33 times and handled at least two innings in 20 assignments. The combination of workload and effectiveness led to 1.4 Wins Above Replacement, an amount that tied Leahy at No. 12 for most WAR in a single season during the team’s 30 seasons of ownership under Bill DeWitt Jr.
The Hardihood Test: Leahy finished the season with a fine 3.07 ERA which was lower (3.04) when stripped of the impact of the defense behind him. But even though manager Oli Marmol made sure to give Leahy enough rest in between his longer relief appearances, the rigorous routine was a challenge.
Over a two-month phase – May and June – Leahy’s strikeout rate dwindled to 15.4 percent, and he was hit for a 3.76 ERA. But in the other four months of the season, covering 61 and ⅓ innings, Leahy had a 25.2 percent strikeout rate and 2.77 ERA.
Leahy’s Best Stat of 2025: I love this one. As I noted earlier, Leahy pitched two innings or more in 20 appearances this past season.
Those 20 lengthier relief assignments totaled 44 and ⅔ innings, and Leahy gave up only five earned runs for a 1.01 ERA. That’s bananas!
Leahy faced 162 batters in these extended relief gigs and opponents got to him for only 27 hits, eight walks and two home runs. His strikeout rate was a solid 25 percent.
That’s fantastic work, across the board, and it tells us a lot about Leahy’s impressive talent, his admirable work capacity, and unique value.
Leahy’s sturdiness was essential in preventing others in the bullpen from being overworked and used up.
And in that context, Marmol’s favorite multi-inning relievers – Leahy and Matt Svanson – are a primary reason why the Cardinals had an outstanding overall bullpen performance for the second straight season.
Despite offloading Ryan Helsley, Phil Maton and Steven Matz at the July 31 trade deadline, the 2025 St. Louis bullpen ranked 3rd in the majors with a 3.65 fielding independent ERA, were 9th in WAR, and had a 63-4 record when leading a game through seven innings.
Can Leahy Become An Effective Starting Pitcher? I think he can and I’ll explain why. But first, I have to issue a qualifier. We’re dealing with smaller sample sizes here, and I’m not sure how 88 innings of robust relief work can translate into 150 or so innings of starting pitching.
But here’s why I like Leahy’s chances of making a reasonably successful graduation to the rotation.
1. Leahy was asked to go longer, and do it more often, than most MLB relievers in 2025. And despite the increased demand, his “stuff” held up well. In his 33 relief outings that lasted more than an inning, Leahy had a 1.81 ERA in 64 and ⅓ innings. If Leahy can capably handle two or even three innings in relief, then getting through five or six innings doesn’t seem like a Mount Everest climb.
2. Leahy scored well above average last season in the Pitching Run Value metric (PRV) at Statcast. His +13 PRV put Leahy among the top 14 percent of all major-league pitchers in 2025. Long story short: he’s good. While noting (again) the differences in sample sizes, here’s a list of major-league pitchers that couldn’t match Leahy’s Pitching Run Value in 2025:
Tyler Glasnow
Sonny Gray
Blake Snell
Logan Gilbert
Dylan Cease
Max Scherzer
Jack Flaherty
Justin Verlander
Tanner Bibee
George Kirby
Joe Ryan
Pablo Lopez
Luis Castillo
Luke Weaver
Michael Wacha
Framber Valdez
Gavin Williams
Logan Allen
Jack Leiter
Jason Adam
Merrill Kelly
Devin Williams
Clarke Schmidt
Emmet Sheehan
Clay Holmes
Zac Gallen
Clayton Kershaw
Shota Imanaga
David Peterson
Quinn Priester
Jacob Misiorowski
Edward Cabrera
Eury Perez
Mitch Keller
Nick Martinez
Aaron Nola
MacKenzie Gore
Chris Bassitt
Michael King
Yusei Kikuchi
Phil Maton
Reese Olson
Kumar Rocker
Nick Lodolo
Bryce Miller
There are more names – but I’ll stop now.
3. Leahy has an excellent pitch arsenal, and that’s what you want in a starting pitcher.
The easiest way to explain this is to list all of his pitches and then show you how each variety rates in Pitching Run Value. Any “plus” is good or better.
* Four-seam fastball, +4
* Slider, +3
* Curve, +4
* Sweeper, +2
* Sinker, +1
* Changeup, minus 1
That’s six different pitches and five are rated above average based on Pitching Run Value. Sure, Leahy has to improve a changeup that did not flummox hitters as much as intended. But then again, he threw the change only 9.6 percent of the time in 2025.
Sure, there are some things in the Leahy profile that raise at least some concern … such as the hard-hit and barrel rates against him. There was a lot of stinging contact against Leahy last season. And I’d prefer to see a more positive percentile for expected ERA, expected batting average against him, whiff-swing rate, and chase rate.
That said, no one is portraying Leahy as a complete pitcher with no weaknesses. He’s thrown only 138 and ⅓ major-league innings and still has plenty of work to do – and plenty to prove. But if we’re talking about a place where talent and potential comes together, I’d say the St. Louis rotation is a good place for that to happen. Especially for a rebuilding team that needs starting pitching. In many ways, it’s ideal timing for giving Leahy a rotation opportunity.
Thanks for reading … If you missed my column yesterday on Albert Pujols and his quest to become a manager, click HERE!
–Bernie
Bernie was inducted into the Missouri Sports Hall of Fame in 2023. During a St. Louis sports-media career that goes back to 1985, he’s won multiple national awards for column writing and sports-talk hosting – and was the lead sports columnist at the Post-Dispatch from 1989 through 2015.
Bernie covered every Cardinals’ postseason game from 1996 through 2014 and was there to chronicle teams that won four NL pennants and two World Series. He provided extensive coverage on the “Greatest Show” St. Louis Rams. Bernie was or still is a longtime voter for the Baseball Hall of Fame, the Pro Football Hall of Fame, and the Heisman Trophy.
You can access his columns, videos and the podcast version of the videos here on STLSportsCentral, catch him regularly on KMOX (AM or FM) as part of the Gashouse Gang, Sports Rush Hour, Sports Open Line or Sports On a Sunday Morning shows. And you can catch weekly “reunion” segments here at STL Sports Central featuring Bernie and Randy Karraker.