Why did Cam Schlittler and Jacob Misiorowski break out, but Eury Perez and Bubba Chandler didn't?

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Why did Cam Schlittler and Jacob Misiorowski break out, but Eury Perez and Bubba Chandler didn't?

Eric Samulski

Thu, October 29, 2026 at 2:52 PM UTC ·

19 min read

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They were dubbed "The Hype Seven." A group of talented young starting pitchers who picked up helium heading into 2026 fantasy baseball drafts. Even though none of them needed to be drafted as aces, fantasy baseball managers were all trying to leave their drafts with at least one of Jacob Misiorowski, Cam Schlittler, Eury Pérez, Nolan McLean, Trey Yesavage, Chase Burns, and Bubba Chandler (and honorary member for the purposes of this article, Emmett Sheehan). These were going to be the pitchers that would lead the charge of the youth wave among the starting pitcher landscape.

Only, some of them failed to complete the journey.

Which is not a new phenomenon. Every spring, a handful of young starting pitchers get anointed as the "next wave" of talent at the position. They have an electric fastball, their breaking pitches produce nasty GIFs of swings and misses, their prospect pedigree is impressive, and their MLB sample size is small enough that everyone gets to imagine the best possible outcome. Every year we talk ourselves into these breakouts, and every year, some of them fail to materialize.

This past season was no different. Only four of the seven (or eight) starters provided the lift that fantasy managers were hoping for. Misiorowski finished as the most valuable starting pitcher in fantasy baseball, according to FanGraphs' Player Rater, with a $43.2 value despite going off the board at pick 114. Schlittler finished second on the Player Rater with a $37.1 value at an ADP of 117. Burns was next closest, with an $18.1 final dollar value, despite an end-of-season innings restriction, at an ADP of 110, and McLean was the only other pitcher to finish with double-digit value at $13.9.

From there, the production fell off a bit.

Eury Pérez finished at just $3.4, despite being the highest-drafted pitcher in the group, with an ADP of 79. Trey Yesavage was ineffective and hurt and finished at -$1.1 of value, Sheehan finished at -$1.7, and Chandler was the worst of the group with a final dollar value of -$8.6, which made him the 204th-ranked starting pitcher on the Player Rater.

So all of that leads to the question: why did we hit on Schlittler, Misiorowski, and, to a lesser extent, Burns and McLean, but miss on Pérez, Chandler, and the others? Is there anything in the 2025 numbers that could have told us in March which of these young pitchers was most likely to break out?

To answer that, I went through 2024, 2025, and 2026 data and created a leaderboard with Stuff+, strikeout rate, walk rate, swinging strike rate (SwStr%), contact rate, zone contact rate, and then individual pitch-level swinging strike rates and movement profiles plus the Pitcher List count metrics that show how often a pitcher gets to two strike counts and how often he finishes them with a strikeout. From there, I did a pass to see how many of those eight starters stood out in enough of those categories, and then I ran the leaderboards through Claude to identify any shared strengths in the 2025 numbers that could have helped us more accurately predict what happened in 2026.

Now, onto the results

Why did Jacob Misiorowski, Cam Schlittler and Chase Burns break out?

It's important to say right off the bat that there wasn't really one thing that all three of these pitchers did the same. That would be nice for the article, but I won't be able to say, "If a pitcher does this, they will have a breakout season." The good news is that means we didn't "miss" anything clear, but the bad news is that we're going to need ot dig through each breakout a little bit to see if we can find some lessons to take away.

Analyzing Jacob Misiorowski's Breakout

For Misiorowski, his breakout was fueled by the fact that his stuff got even better, and the walks that were a concern for him in the minors disappeared. He was already the top Stuff+ arm in this group in 2025 with a 116.4 mark. In 2026, that jumped to 128.0; yet, the more change was likely his walk rate. In the minors in 2024, he walked 14.4% of hitters, which prompted people to suggest that he had "reliever risk." In 2025, his walk rate dropped to 10.8% in the big leagues. That's still an elevated number but a much better one, and then, in 2026, that improved again, dropping down to 6.5%.

The natural follow-up question would be, why did his walk rate improve?

The first answer is that he made a pitch mix change, adding in a cutter this season. You could also argue that he turned his slider from 2025 into more of a cutter and then added a slider, but it's semantics. Misirowski added in a harder cut fastball that he used early in the count. It was a good strike pitch, but the biggest benefit of the pitch was that it kept hitters from sitting on his four-seam fastball.

In 2026, his four-seam strike rate increased from 66% to 69.4% even though he threw four-seamers in the zone far less often. His four-seam SwStr% went from 16.2% in 2025 to 20.6% this year, and that new, slower slider posted 20.9% SwStr%. Having that cutter for strikes allowed him to elevate his four-seamer more often, and his overall strikeout rate went from 32.3% to 38.2%, while his walk rate dropped from 10.8% to 6.5%. That's a K-BB% of 31.3% over 174.2 innings, with a 1.80 ERA and a 0.80 WHIP.

Was there a way to know Misiorowski would improve his command? Not entirely, but adding a strike pitch would have been the first clue that it could happen. It's the same thing that happened to Cade Cavalli in the middle of the season when he added a cutter to his pitch mix in June and took off.

There were also mechanical issues that Ben Brewster of Tread Athletics breaks down well in the post below. Misirowski got stronger in his lower half, but also shifted where he held his weight in his load, had more bend in his back knee, and a few other mechanical tweaks that helped him improve his balance and be more direct to home plate. None of that we could have known until we had actually seen him pitch in 2026.

Analyzing Cam Schlittler's Breakout

Unlike Misirowski, Schlittler's stuff didn't really change at all. His Stuff+ was 112.4 in 2025 and 113.4 in 2026. However, what did change was how that plus stuff played. This season, Schlittler's strikeout rate rose from 27.6% to 31.3%, his walk rate fell from 10.2% to 6.3%, and his contact rate allowed dropped nearly five points, from 77.9% to 73.0%. His Location+ went from 97.8 to 102.2, which is a nice jump, and his curveball took a step forward with an 18.2% SwStr% after posting a 10.2% mark in 2025.

However, much like Misirowski, the key to his stuff playing up may be in his four-seam locations. Schlitter's SwStr% on his four-seamer rose from 14.5% to 19.2% despite the fact that he was throwing the pitch in the zone less often. They were both "missing" the zone in the same place: upstairs. While Misirowski had added the cutter, Schlittler saw his sinker usage jump from 6.5% in 2025 to 19.3%. Even though the sinker wasn't as specifically an early-strike pitch as Misirowski's cutter was, it had an above-average strike rate, and the increased usage allowed Schlittler to then throw the four-seamer over the top of it, often out of the zone.

For both pitchers, their four-seam SwStr% jumped at least 4.4%, and the increase wasn't strictly because of shape or velocity. When you look at year-over-year trends, velocity, vertical break, and horizontal break explain about 12% of the variation in four-seam SwStr% across starters. Both pitchers' four-seamers beat what their shape predicted by about 7% (+6.7 for Misiorowski, +7.1 for Schlittler). Since their over-performance does not show up when compensating for velocity and movement, location is likely the key component.

For both pitchers, increasing the reliance on additional fastball variations allowed them to elevate their four-seamer more often, which led to massive gains in swinging strikes and a reduction in contact.

What actually predicts a young pitcher's breakthrough?

The simple answer here is that Stuff+ is the best single predictor I found.

When combing through the leaderboards, I filtered out pitchers with little MLB experience going into 2026 (I decided on fewer than 160 combined innings between 2024 and 2025) who threw 90 or more innings this year. 43 pitchers came back, so I checked their stats from 2025 to see if anything correlated to their 2026 success. It turns out that their 2025 Stuff+ grades correlated with their 2026 SIERA at -0.59 and with their 2026 K-BB% at +0.61.

I haven't been a Math person since 10th grade, so I had to learn that correlation runs from −1 to +1. A correlation of 0 means there is no relationship, and a correlation of ±1 means it's a "perfect lock." The -0.59 score means that as Stuff+ goes up, SIERA goes down; pitchers with higher Stuff+ had lower SIERAs the next season. Meanwhile, the +0.61 means that as Stuff+ goes up, K-BB% also goes up; pitchers with higher Stuff+ had higher K-BB%s the next season.

While 0.60 correlation scores don't seem overly high, it's a fairly strong indicator and is on par with Stuff+ year-to-year or strikeout rate year-to-year. So, we know that Stuff+ is the best predictor of next year's SIERA or K-BB%, which is crucial for predicting fantasy baseball success, but what about the other stats in my leaderboard?

All the command and sequencing stats (walk rate, Location+, first-pitch strike rate, etc.) didn't add any predictive value beyond what Stuff+ already told us. Zone rate did add about 4% to how much year-over-year variation we can explain or predict. SwStr% did correlate to next year's K-BB%, but once again, added nothing once Stuff+ was accounted for, and SwStr% on four-seam fastballs correlated well to next year's K-BB% but only added marginal value once Stuff+ was factored in.

Four-seam SwStr% was an interesting one to me. I had expected it to be more predictive than it was. When I looked at just the 43 pitchers mentioned above, it showed a strong correlation with next year's K-BB%. Pitchers whose fastballs weren't missing bats in 2025 performed meaningfully worse the next year, particularly in terms of SIERA. Yet, when I expected that search to the entire starting pitcher pool, the correlation got worse, so four-seam SwStr% is maybe more of a tiebreaker than a real predictor. It is also potentially volatile in small samples since Bubba Chandler had a 16.5% SwStr% on his four-seamer in 2025 and that dropped to 10.8% in 2026 while he finished as the worst pitcher in the hype seven group.

Another surprising thing was that minor league command doesn't appear to be much of a predictor on its own. I know it makes sense to avoid young pitchers who can't throw strikes, but the data didn't support that. When I took 2024 Triple-A data and then crosschecked that with 2025 MLB performance, the highest-walk quartile of 2024 minor-league pitchers had an 11.4% walk rate that season in Triple-A, but those same arms finished with an 8.5% walk rate in the majors in 2025. The same type of thing happened when I compared 2025 minor league numbers to 2026 MLB numbers. Misiorowski's Triple-A walk rate last season was 12.3%, but his MLB walk rate this season was 6.6%. Schlittler had a 9.2% walk rate in Triple-A last year and a 6.4% rate this year. I know we can argue that those two pitchers are anomalies, and some pitchers who have poor command will certainly never figure it out, but data research over the last three seasons seems to show that walk rates for young pitchers are more fixable than we assume, so they are not a stable predictor until that pitcher has a real MLB sample size to use.

So the basic answer to what predicts a young starting pitcher's breakthrough appears to be a high Stuff+ grade, a good K-BB%, and a four-seamer that gets swinging strikes.

I'll have some arms you should target in 2027 listed at the end of this article.

Why did Eury Pérez, Trey Yesavage, and Bubba Chandler not hit?

Now that we've examined the successes, we should look at the misses and see what we can learn from them.

Pitcher	2026 IP	Stuff+ (2025 → 2026)	K-BB% (2025 → 2026)	Contact% (2025 → 2026)	2026 ERA / SIERA
Eury Pérez	158	115.3 → 113.9	19.0 → 15.1	73.5 → 73.5	3.93 / 4.07
Nolan McLean	179.2	108.5 → 107.1	21.8 → 16.6	74.1 → 78.3	3.16 / 3.80
Trey Yesavage	97.2	107.0 → 107.8	14.5 → 12.5	67.3 → 71.4	3.69 / 4.48
Bubba Chandler	148.2	101.8 → 100.7	24.7 → 8.4	71.4 → 80.0	4.54 / 4.86
Emmet Sheehan	112.1	102.7 → 100.4	25.7 → 20.9	68.9 → 70.8	4.57 / 3.42

The one that obviously stands out the most is Eury Pérez. He was the highest-drafted pitcher in this group, so his season was a big disappointment when put up against our expectations. His 2025 Stuff+ was 115.3, which was better than Schlittler's. His SwStr% was in the 90th percentile and his contact rate in the 85th. He should have been a breakout arm this season. So what happened?

Well, Pérez's contact rate allowed didn't change from 2025 to 2026 while both Misiorowski and Schlitter made meaningful gains. His strikeout rate decreased by 1.5% while they both had increases, and his walk rate increased by 2%, while they both had large decreases. His SwStr% stayed essentially the same, while Misiorowski's rose by about 4% and Schlitter rose by almost 3%. His Location+ score also fell five points.

Some of this could be tied to his four-seamer. In 2025, Pérez had a 12.3% SwStr% on his four-seamer, which was already below Schlittler and Misiorowski, but not tremendously so. However, while they improved their four-seam SwStr% meaningfully, Pérez saw his increase just about 1%.

He also added in a sinker this season, much like Schlittler, but the issue was that Pérez had terrible command of his. It had a 4th percentile zone rate and a 20th percentile strike rate. The intention was there, but he wasn't actually using another fastball variation for strikes. While he did also increase his high fastball usage by 13%, it's still below average, so he's not really throwing his four-seamer on top of the secondary fastball, as Misiorowski and Schlittler did. Again, that's not really something we could have known going into the season unless we watched in spring training and saw that the sinker was not even close to being a strike pitch.

There was one small red flag there. His four-seam swinging strike rate was 77th percentile among starting pitchers. That's fine, but not potentially elite. In 2025, he also had just a 17.6% PutAway Rate, which was 35th percentile among starting pitchers; yet, he had a 98th percentile two-strike rate. So he got into plenty of two-strike counts in 2025 but struggled to put hitters away. That maybe should have set off a few more alarm bells than it did. He also gave up more hard contact and barrels than the league average last year. Another small red flag that, when added to the other ones, should have put us off the breakout call.

The other failed breakouts are a bit easier to predict. Trey Yesavage did battle injuries this year, but he had a massive command issue in 2025. In his small MLB sample, he had a 90.6 Location+, which is well below average and easily the worst of this group. He also had a 15.3% walk rate in Triple-A last year and an 11.3% mark in his MLB debut sample. On top of that, his four-seamer is just 94.7 mph and had an 8.3% SwStr%, which was 33rd percentile. His Stuff+ seems to be entirely carried by his splitter, and not much in his profile matched with the pitchers who did break out.

We also talked a little bit about Bubba Chandler already, but his being in this group was likely more off of prospect pedigree than anything. His Triple-A walk rate in 2025 was 12%, but many people, myself included, found a way to explain that away. His Stuff+ in his 31.1 MLB innings last year was 101.8, which is not close to the other names in this group. In fact, among pitchers with a 2025 Stuff+ under 104, only 4% finished in the top 30 starting pitchers in 2026.

We should note that Emmet Sheehan's stats still look pretty good in comparison. No, he didn't improve the way that Misiorowski and Schlittler did, but his K-BB% was still 21%, easily the highest of this group. His contact rates are still good, and his SIERA was far and away the best of this bunch. His four-seam SwStr% was also 15.9% this season. I'm still going to be very in on Sheehan in 2027.

How possible is it to project who will take the step forward?

To answer this, I took the 94 pitchers with little MLB experience who threw at least 30 innings in 2025 and checked how many finished among the top 30 starters by fantasy value in 2026.

2025 profile	Pitchers	Top-30 in 2026	Top-30%	Reached 90 IP %
All	94	12	13%	37%
Stuff+ 108 or higher	7	5	71%	71%
Stuff+ 104 to 108	10	4	40%	40%
Stuff+ under 104	77	3	4%	34%
Stuff+ 108+ and K-BB% 18%+	5	4	80%	80%
Stuff+ under 108 and K-BB% 18%+	11	2	18%	64%
Stuff+ under 104 and K-BB% under 18%	68	2	3%	29%

There were 17 pitchers from that group with a Stuff+ of 104 or higher, and nine of those pitchers finished inside the top 30 this season. That is a very real signal. However, as I've mentioned before, it's not foolproof. Pérez had the best Stuff+ of the group, and we discussed how his season went. All of Parker Messick, Sean Burke, and Logan Henderson were below that 104 Stuff+ line, and both Messick and Burke were under 100.

The other factor is that only 37% of that 94-pitcher group even reached 90 innings in 2026. You can't break out if you don't hold a rotation spot. So, if we're looking for breakouts in 2027, we do need to lean heavily into job security (easier said than done) and then rank potential targets by Stuff+, then K-BB%, then four-seam SwStr% and a pseudo tiebreaker. Then keep watching for strikeouts and contact rates early in the season, and pitch mix changes that may allow for increased SwStr%, since those were all the things that really set Misiorowski and Schlittler apart.

Which young pitchers could take the step in 2027?

If we apply that same thought process to pitchers who are 26 or younger and threw 70 or fewer MLB innings in 2026, we can find a short list of targets. It should be noted that a Stuff+ of 104 is a strong mark, so this is not a list of pitchers who could be good; it's meant to be a list of pitchers who could have a true breakout since that delineation seems to be a clear cutoff, based on the research above.

Pitcher	2026 MLB IP	Stuff+	K-BB%	4-seam SwStr%	Why he is on the list
Jackson Jobe (DET)	46	102.9	18.1%	10.8%	Closest fit to the Stuff+ and he hits the K-BB% 18%+ group. 3.61 SIERA and a clear rotation path.
Anthony Molina (SFG)	34	101.7	17.6%	10.7%	Like Jobe, his 4-seam SwStr% isn't elite, but that's a tiebreaker. Good signals on Stuff+ and K-BB%
Hagen Smith (CHW)	28	107.7	22.7%	11.5%	Pitched in relief, but hits the signals loudly. AAA BB% is a concern, but so was Misiorowski's
Didier Fuentes (ATL)	73.1	115.2	23.9%	15.9%	Also pitches in relief, but elite Stuff+ and 4-seam SwSrr%. Feels like a real breakout
Spencer Miles (TOR)	95.2	100.1	17.5%	13.4%	Primarily a sinkerballer, but Stuff+ and K-BB% both are near the thresholds. Does he have a job?
Kade Anderson (SEA)	35.2	96.9	15.8%	10%	We know the AA numbers are stupid. The MLB Stuff+ and 4-seam SwStr% are modest
Jonah Tong (NYM)	20.2	95.8	23.0%	13.8%	Stuff+ isn't great, and command is an issue, but 4-seam SwStr% and K-BB% are strong

If we lowered the Stuff+ threshold a little bit, we could also include Blade Tidwell, who had a 99.1 Stuff+, but his 9.6% K-BB% isn't really a hit. Three notable prospects spent most of 2026 at Double-A, so we don't have Stuff+ grades of pitch-specific swinging strike rates. However, Ryan Sloan (SEA), Gage Wood (PHI),and Anthony Eyanson (BAL)would all be interesting if they get an MLB job this season. They all had elite K-BB% rates in the minors; Sloan has impeccable command, and Wood's 35.6% overall whiff rate is tremendous. You'd not be drafting these guys around the players listed above because we simply don't have the data on them, but they would be names to watch, with Sloan being the best bet to win a job right away in 2027.

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