When the St. Louis Cardinals decided late last year to move Kyle Leahy into a full-time starting role, the decision initially raised plenty of questions.
Leahy, now 29, did not arrive at the starting-pitcher job through the traditional path. His earlier minor-league record as a starter offered little indication that he would eventually become a legitimate Major League rotation option. His last extended experience as a starter in Double-A had produced numbers that looked fairly ordinary and resembled the profiles of many pitchers who never ultimately establish themselves in the majors.
At that point, it was difficult to know exactly what Leahy was.
Was he a traditional starter? A long reliever? A swingman capable of moving between roles? Or perhaps a pitcher who was good enough to handle several jobs but not dominant enough to permanently occupy one?
His recent major-league performance, however, began challenging those assumptions.
A Pitcher Who Refused to Fit Into One Category
Leahy started to show signs of promise in 2024. His versatility became even more apparent in 2025, when the Cardinals asked him to handle virtually every role imaginable.
He worked out of the bullpen, handled multiple innings, entered games in different situations and eventually even received a starting assignment.
The workload was significant.
Leahy threw 88 innings in relief in 2025, a substantial amount for a pitcher working primarily as a reliever. Yet rather than breaking down or becoming ineffective, he continued to produce.
That performance eventually convinced the Cardinals to give him a larger opportunity as a starter.
There was still uncertainty surrounding the decision. One reasonable interpretation was that Leahy might be a useful “tweener”—a pitcher who was better than a typical reliever but perhaps not quite good enough to be a dependable full-time starter.
The Cardinals, however, decided to find out.
Nearly two years of additional information now provides a much clearer picture.
Leahy Has Been Better Than Expected in 2026
Through the end of August, Leahy had accumulated approximately 2.4 fWAR as a starter in 2026.
That figure ranked him around 40th among MLB starting pitchers, putting him in roughly the same range as fellow Cardinals pitcher Andre Pallante.
That is a respectable accomplishment, particularly for a pitcher who entered the season with so many questions surrounding his ability to handle a starting workload.
Some observers might classify a performance at that level as that of a solid No. 2 starter.
There is reason to be slightly more conservative.
The best rotations in baseball, such as those of Seattle, New York and Philadelphia, often have several pitchers producing significantly more than 2.4 fWAR. In some elite rotations, multiple starters have already accumulated more than twice Leahy’s total.
That does not diminish what Leahy has accomplished.
Rather, it places his performance in context.
On a very strong rotation, his production might profile more naturally as a No. 3 or No. 4 starter.
And that is still an extremely valuable outcome for a pitcher whose path to the rotation was anything but conventional.
His Performance Has Improved Dramatically During the Season
Perhaps the most interesting part of Leahy’s 2026 season is not his overall performance but the direction in which it has moved.
His monthly underlying numbers tell an important story:
Month FIP xERA xFIP K-BB% K% BB%
April 5.57 6.28 4.21 8.2% 16.4% 8.2%
May 3.75 6.85 4.32 11.2% 20.7% 9.5%
June 3.01 4.42 4.24 11.1% 19.4% 8.3%
July 3.32 3.35 3.11 20.4% 24.5% 4.1%
August 0.87 3.11 2.15 29.3% 32.1% 2.7%
Overall 3.51 4.85 3.69 14.7% 21.7% 7.0%
The progression is striking.
Leahy struggled in April, with a 5.57 FIP and an 8.2% K-BB rate. By May, his FIP had dropped below 4.00, suggesting that his underlying performance was improving even though his expected ERA remained elevated.
The real transformation began around June and became much more obvious in July and August.
By August, Leahy’s FIP had fallen all the way to 0.87, while his K-BB% climbed to an outstanding 29.3%.
That is a completely different pitcher from the one who opened the season.
FIP Provides an Important Clue
FIP is one of the most useful starting points when evaluating a pitcher’s underlying performance because it focuses primarily on outcomes a pitcher has greater control over, including strikeouts, walks, hit batters and home runs.
Leahy’s overall 3.51 FIP is particularly encouraging.
A FIP below 4.00 generally represents solid work, while a number around or below 3.50 moves into considerably stronger territory.
The relationship between his FIP and his other expected statistics is also fascinating.
Leahy has consistently outperformed his xStats over his MLB career. That could partly be explained by his home environment, the defense behind him or his ability to limit certain types of damaging contact.
But because the pattern has continued over multiple seasons, it becomes increasingly difficult to dismiss his success as simple good fortune.
There appears to be something real in his approach.
The July and August Transformation
The biggest question surrounding Leahy now is what changed around the middle of the season.
His K-BB% jumped dramatically beginning in July.
That statistic is especially important because it combines the two things a pitcher wants most: increasing strikeouts while limiting walks.
Leahy’s strikeout rate improved, but his walk rate also dropped sharply.
In July, he posted a 24.5% strikeout rate with only a 4.1% walk rate.
Then came August.
His strikeout rate reached 32.1%, while his walk rate fell to just 2.7%.
That combination is elite.
The question is whether it represents a genuine evolution in his pitching or merely a short-term hot streak.
Six Pitches Give Leahy an Unusual Advantage
One reason Leahy may be able to outperform expectations is the depth of his arsenal.
He uses six different pitches, giving hitters considerably more to think about than they might against a pitcher who relies heavily on only two or three offerings.
None of his individual pitches possesses overwhelming movement across the board. However, his sweeper and slider demonstrate particularly useful horizontal movement.
The depth of the arsenal itself can make each pitch more effective.
Against a two-pitch pitcher, a hitter can often eliminate certain possibilities based on the count, situation or previous at-bats. If one pitch is not working for strikes, the hitter can simply focus on the other option.
Leahy presents a different problem.
Even if a hitter anticipates one pitch, the pitcher still has several alternatives available.
That uncertainty can make the entire arsenal more effective.
A Balanced Pitch Mix
Leahy also does not overwhelmingly rely on one particular pitch.
His individual offerings generally fall between roughly 13% and 27% usage, with his four-seam fastball representing the most frequently used pitch.
Even that fastball is used only around 27% of the time, which is relatively modest compared with many starters.
That balanced distribution makes it harder for hitters to sit on one particular offering.
More importantly, Leahy appears to have gradually moved away from his fastball as the season progressed.
That adjustment may be one of the most important developments in his transition from reliever to starter.
Hard Contact Has Declined
The Statcast data initially presents some concerns.
Leahy’s full-season HardHit% ranking has been poor, sitting around the 2nd percentile in the referenced data.
At first glance, that is a major red flag.
However, the full-season number is heavily influenced by his early struggles.
His hard-contact rate has steadily declined throughout the season. By the middle of the year, it had moved below league-average territory.
That raises an important question:
Is the full-season number simply lagging behind the pitcher Leahy has become?
The evidence increasingly suggests that may be the case.
His xwOBA has followed a similar downward trajectory, reinforcing the idea that opposing hitters have been producing less damaging contact against him as the season has progressed.
The Fastball May Be the Key to the Change
The most interesting correlation involves Leahy’s pitch usage.
As his reliance on the fastball has declined, his HardHit% and xwOBA have also improved.
At the same time, he has increased his use of breaking and off-speed pitches.
That does not automatically prove cause and effect, but the timing is difficult to ignore.
His four-seam fastball has a Stuff+ rating of 93, which is below average.
By comparison, his sinker has a 115 Stuff+ rating and his slider is at 111.
That tells us something important.
Leahy may simply have recognized that his fastball is not his best weapon and adjusted accordingly.
Rather than repeatedly challenging hitters with an average-or-below-average fastball, he has increasingly leaned on pitches that possess better characteristics.
His Sinker and Breaking Balls Are His Weapons
Leahy’s sinker stands out as one of the most effective components of his arsenal.
His slider also grades well, while his sweeper and curveball provide additional breaking options.
His curveball and cutter have lower Stuff+ ratings—around 95 and 93 respectively—but they still contribute to an unusually diverse repertoire.
His overall Location+ rating of 105 is another encouraging indicator.
That suggests his ability to locate his pitches is a meaningful part of his success.
Pitching+ also views him as slightly better than league average in 2026, as well as across his MLB career.
In other words, Leahy does not need one dominant pitch to succeed.
His formula is based more on pitch selection, location, movement, deception and variety.
Pitch Tunneling Adds Another Layer
Another fascinating part of Leahy’s profile is how he tunnels his pitches.
Pitch tunneling refers to the ability to make different pitches initially appear similar to a hitter before they diverge as they approach the plate.
This makes it more difficult for hitters to identify the pitch early.
Leahy’s four-seam and sinker, for example, leave his hand with similar spin directions while ultimately producing different movement.
His changeup also works reasonably well from a tunneling perspective with his fastballs, although the pitch itself does not always generate ideal results.
The changeup lacks enough late fade, and the velocity difference from the fastball is not dramatic enough to make it consistently deceptive.
His sweeper and curveball are particularly interesting.
They can initially present similar visual information to a hitter but then move dramatically differently on the way to the plate.
That combination can create considerable uncertainty.
The Sinker-Sweeper-Curve Combination
The sinker, sweeper and curveball appear to be the foundation of Leahy’s pitching strategy.
All three pitches generate positive run-value results, with some grading in particularly strong territory.
His slider is somewhat less deceptive from a tunneling standpoint but remains an effective pitch independently.
This gives Leahy a fascinating combination:
A useful sinker
A strong sweeper
A quality curveball
An effective slider
A changeup
A four-seam fastball
That is a lot for hitters to process.
The Third-Time-Through Problem
There is, however, one significant concern.
Leahy’s performance deteriorates dramatically when he faces a lineup for the third time.
His numbers by times through the batting order illustrate the issue:
Times Through Order FIP xERA xFIP K-BB% K% BB%
1st 2.68 3.38 3.31 18.7% 25.8% 7.1%
2nd 3.19 4.35 3.54 1.5% 21.6% 6.1%
3rd 6.64 13.19 5.26 3.2% 11.8% 3.6%
Overall 3.51 4.85 3.69 14.7% 21.7% 7.0%
The third-time-through numbers are concerning.
His FIP jumps from 3.19 to 6.64, while his strikeout rate drops from 21.6% to just 11.8%.
His K-BB% falls to only 3.2%.
There is an important caveat: Leahy has thrown only about 19 innings the third time through the order, so the sample is extremely small.
Still, the magnitude of the decline is difficult to ignore.
Why Does Leahy Struggle the Third Time Through?
There are several possible explanations.
One could simply be stamina.
Leahy spent much of his recent career as a reliever, so his body is still adapting to the demands of a starter’s workload.
Another possibility involves his pitch mix.
Because his fastball is not a dominant offering, he may need to show more of his breaking pitches earlier in games.
That creates a potential problem later.
The more times hitters see those pitches, the easier it becomes to recognize them.
His sinker, in particular, may become easier to identify after hitters have seen it several times.
Once hitters begin recognizing the pitch earlier, they can either attack it directly or eliminate it from consideration.
Either outcome reduces the advantage created by having a six-pitch arsenal.
The third-time-through issue will therefore be one of the biggest things to monitor as Leahy’s starting career develops.
His Workload Is Another Major Concern
Perhaps the biggest long-term concern isn’t his pitch mix or even his third-time-through performance.
It is his workload.
Leahy is establishing career highs in innings and overall pitching activity.
That matters because pitchers transitioning from relief work into starting roles can experience a significant increase in physical demands.
Starting requires more pitches per appearance, more time between outings under a different routine, more total innings and greater overall stress on the arm and body.
A dramatic increase in workload can sometimes affect a pitcher’s effectiveness the following season.
It can also increase injury risk.
For that reason, the Cardinals will need to carefully monitor Leahy’s workload both during the remainder of 2026 and entering the 2027 season.
Which Kyle Leahy Is the Real One?
Perhaps the biggest question surrounding the pitcher now is simple:
Which version of Kyle Leahy should we believe?
Was the April and May pitcher the real Leahy?
Or is the July and August version the pitcher the Cardinals have discovered?
His June performance may represent an interesting middle ground.
The season has essentially provided examples of both his floor and his ceiling.
Early in the year, he struggled with contact, strikeout production and command.
Later, he dramatically improved his ability to miss bats while simultaneously cutting down his walks.
That kind of improvement is exactly what the Cardinals want to see from a pitcher transitioning into a permanent rotation role.
Can the Improvement Continue?
The biggest challenge now is determining whether Leahy’s recent transformation is sustainable.
A 29.3% K-BB rate in August is outstanding, but one month is not enough to establish a new baseline.
The league will eventually adjust.
Hitters will study his pitch selection.
They will receive more information on his tendencies.
They may begin anticipating his breaking pitches more effectively.
The key for Leahy will be demonstrating that his adjustments are flexible enough to survive those counter-adjustments.
If he can continue generating strikeouts while keeping his walk rate low, he could establish himself as a dependable middle-of-the-rotation starter.
What the Cardinals Have Discovered
The most encouraging conclusion from Leahy’s development is that the Cardinals may have uncovered a legitimate starting pitcher in a place where few people expected to find one.
He did not dominate the minor leagues as a traditional starter.
He did not enter the majors with the profile of a highly touted rotation prospect.
Instead, he gradually built value by becoming increasingly adaptable.
His experience as a reliever appears to have helped him develop a broad arsenal and an understanding of how to attack hitters in different situations.
Now, the Cardinals are asking him to take those skills and stretch them across a starter’s workload.
So far, the results have been promising.
Overall Assessment
Leahy may never become an ace, and there is little evidence at this stage to suggest that he belongs among baseball’s elite starters.
But that is not necessarily what the Cardinals need from him.
A pitcher who can consistently deliver league-average or better innings, limit walks, generate ground balls and provide roughly 2–3 wins above replacement can be extremely valuable over a full season.
Leahy’s current profile suggests he has the potential to do exactly that.
His 3.51 FIP, strong ground-ball rate, improving strikeout numbers, low walk rate and diverse pitch mix provide a solid foundation.
The improvements during July and August make the profile even more intriguing.
The Biggest Questions Moving Forward
Several questions will determine whether Leahy can turn this promising season into a sustainable career as a starter.
First, can he maintain his improved strikeout and walk rates?
Second, will hitters eventually adjust to his expanded use of breaking pitches?
Third, can he find a reliable way to navigate opposing lineups for a third time?
Fourth, can his arm and body withstand the increased workload after spending much of his career in relief?
And finally, which version of Leahy is closest to his true talent level—the struggling pitcher from April, the improving version from June, or the dominant-looking pitcher who emerged in July and August?
Those questions may not be answered until next season.
Final Outlook
Kyle Leahy’s journey to the Cardinals’ starting rotation has been unconventional, but that may be precisely what makes his development so interesting.
At 29, he is not the typical young pitching prospect being groomed for a breakthrough. Instead, he is an experienced pitcher who has spent years adapting to different roles and gradually discovering what works.
His 2026 season suggests that the transition to starting pitcher is beginning to make sense.
He has a deep arsenal, useful ground-ball ability, good command, multiple effective breaking pitches and the intelligence to adjust his pitch mix when something is not working.
The most encouraging development has been the improvement over the course of the season.
His fastball usage has declined, his breaking-ball usage has increased, his hard-contact rate has fallen and his strikeout-to-walk profile has improved dramatically.
There are still legitimate concerns, particularly his third-time-through struggles and the unprecedented workload he is accumulating.
But if the July-August version of Kyle Leahy is closer to the pitcher he can become, the Cardinals may have found a surprisingly valuable rotation piece.
Perhaps the most intriguing question is also the simplest: would Leahy’s emergence look even more impressive if it had happened when he was 24 or 25 rather than 29?
Age may limit his long-term upside, but it does not diminish what he has accomplished.
The Cardinals took a chance on a pitcher who did not fit neatly into the traditional starter-or-reliever categories.
Now, after nearly two years of major-league evidence, Leahy is beginning to look less like a temporary experiment and more like a legitimate starting pitcher.
Leave a Reply