Cardinals' Hurler Used Aptitude, Six-Pitch Mix to Thrive in 2026

Growth, as St. Louis Cardinals’ manager Oliver Marmol pointed out repeatedly over the final month of the 2026 season, can be measured in a variety of ways.

One way, of course, is the standings – an area where the Cardinals fell back a win from 2025 (78-84) to 2026 (77-85), one that was somewhat expected with the widespread youth on the roster and the club selling off veteran pitchers JoJo Romero and Dustin May for prospects at the MLB Trade Deadline.

Instead, the Cardinals tried to evaluate areas of growth in non-traditional ways in a non-traditional season in St. Louis.

Growth was having a defined core group of players – Alec Burleson, Jordan Walker, JJ Wetherholt, Ivan Herrera, Masyn Winn, Michael McGreevy, Kyle Leahy and Riley O’Brien – take major steps in their games and evolve into building blocks.

Growth was seeing Leo Bernal, Joshua Baez, Quinn Mathews, Cooper Hjerpe and Nathan Church live up to the hype that followed them from the Minor Leagues and show signs they can be depended on going forward.

Growth was Andre Pallante and Gordon Graceffo shaking off the struggles of 2025 and showing the fortitude to change the trajectory of their careers.

“This is a really young group, but there’s been a lot of progress with so many of these guys,” Marmol said. “You can go up and down the lineup and you see growth from so many of our guys. Then, go to the rotation and what McGreevy, Pallante and Leahy did this season, and the bullpen as well. Our staff has really enjoyed pouring into that group. They are hungry for information and they want to be coaches, so that’s made it a lot of fun.”

However, as president of baseball operation Chaim Bloom reminds, the Cardinals still have major gulfs between them and MLB’s top teams. The National League champion Brewers, after all, finished 26 games ahead of St. Louis and battered the Cards in 11 of 13 head-to-head meetings. Much more growth is needed for the Cards to better navigate the difference the rebuilding and contending.

With growth being the focus, let’s look back at the performances by individual players in the 2026 season and how they will figure into the Cards’ plans going forward in 2027 and beyond:

Player name: Kyle Leahy

Age: 29

How acquired: Selected by Cardinals in 17th round of 2018 MLB Draft

2026 statistics: 30 games/30 starts, 10-5. 3.66 ERA, 140 IP, 15 HR allowed, 132 strikeouts, 41 walks, .269 batting average allowed

Key numbers: From June 23 to Aug. 9th, Leahy had 12 straight starts with at least five innings pitched and two or fewer earned runs allowed (save for a July 12 start limited to three innings by rain). Leahy had a 1.38 ERA over five starts in July and a 1.64 ERA over five starts in August.

Looking back to 2026: Making the transition from the bullpen to the starting staff, Leahy initially had some struggles getting through the lineup a third time, but he pushed through that and became the Cards’ most dependable pitcher for long stretches of the season. Computer projections aren’t fond of Leahy’s chances of long-term success as they had him with an expected ERA of 4.89 and an expected batting average allowed of .272 – higher than his actual 3.66 ERA and his .269 batting average allowed. But Leahy is one of the smartest players on the staff and he knows how to pitch around hard contact by beautifully mixing his pitches. With the 6-foot-5, 225-pound right-hander pitching the most innings in his career, the Cardinals purposefully shortened his outings late in the season and it cause his sharpness to decline. After going 3-0 with a 1.64 ERA in August, his effectiveness sipped in September (0-1, 10.13 ERA) when he was limited to 40-50 pitches in starts.

Looking forward to 2027: Leahy established himself as a potential front-of-the-rotation starter in 2026, and the Cardinals desperately need him to take another step forward in 2027. Some of the advanced analytics are concerning with Leahy, such as his average exit velocity allowed (91 mph) ranking in MLB’s bottom 2 percentile and his chase rate (27.2 percent) sitting in the 14th percentile. However, Leahy makes up with what he lacks in stuff with guile and an understanding of pitching. His ground ball rate (45.8 percent) ranks in the 70th percentile and his low walk rate (6.9 percent) are in the 76th percentile speak to his ability to navigate traffic and pitch out of jams.

Denton’s analysis: A big part of Leahy’s brilliance as a pitcher is his ability to mix his pitches and never rely too much on one pitch. His four-seam fastball sits at just 94.3 mph, but it plays faster because of his extension (7.3 feet, 97th percentile) and his other pitches. Here is a look at how balanced Leahy’s arsenal is, the average velocity and how often he throws each pitch: Four-seam fastball, 94.3 mph, 26.3 percent; curveball, 83 mph, 16 percent; slider, 89.4 mph, 16 percent; changeup, 88.6 mph, 15 percent; sweeper, 84.8 mph, 14 percent; and sinker, 94.2 mph, 13 percent. Any struggles Leahy endures likely will be short-lived because of his high aptitude and his ability to analyze his performances between starts.