Starting Pitcher Arsenal Changes - Pitch Mix Analysis for Fantasy Baseball (Week 11)

June 7, 2025

Corbin Young examines several fantasy baseball pitcher risers and sleepers displaying changes in their pitch mix, movement, and velocity heading into Week 11 (2025).

Welcome back, RotoBallers, to my weekly "Starting Pitcher Arsenal Changes" article series for Week 11 of the 2025 fantasy baseball season. We researched 30 starting pitchers so far, with three more in this column, all of whom were consistent veterans with ace-like outcomes. Today's article will discuss a few starting pitchers who made actionable adjustments, like a release point change or a new pitch, location changes, and whether they matter moving forward.

For those new to this column, we cover a few starting pitchers and their arsenal changes via pitch mix, velocity, and movement each week. Since it's early, we're looking for new pitches, velocity, and movement changes. When we find significant release point shifts, it can potentially impact their movement profiles in 2025.

Pitchers can make notable changes in smaller samples, so let's see if we can find something with these starting pitchers. Statcast provides so much data to digest and compare quickly to past seasons. Let's look through my process of examining starting pitchers and their arsenals. Reach out to me on X if you have a pitcher and have questions about it. Thank you for reading!

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Is Kevin Gausman's Splitter Back?

In Gausman's peak seasons before 2024, his splitter had 25-26 percent swinging strike rates (SwK). However, Gausman's splitter SwK fell to 16 percent (2024), then started slow in March and April (13.2 percent). We've seen an uptick in whiffs via the splitter in May, jumping to a 23.4 percent SwK.

So, what changed? Gausman's splitter added two inches of downward movement (33.5 inches) and lost nearly two inches of arm-side fade (16.1 inches) compared to March/April 2025. That's a bit closer to the 2022 and 2023 versions of the splitter, though sometimes pitches can fluctuate by about two inches from month to month or by season.

Besides Gausman's splitter movement changing slightly and the additional whiffs, he has been throwing it more (41.7 percent) in May, up from 32.1 percent (March/April). Once again, Gausman's splitter usage in May aligns closer to the previously high pitch percentages in peak seasons. The other question involved whether Gausman located his splitter differently in May, though it's worth noting that we're dealing with small samples.

The splitter locations appear nearly identical, although the heat maps indicate increased usage in May. The splitter zone rates increased to 35.8 percent (May) from 32.2 percent (March/April). However, hitters were chasing the splitter nearly 40 percent of the time, a seven percentage point increase in May compared to March and April.

Does Gausman Have Anything Else?

It's great to see Gausman's splitter working well in May, but does he have anything else? Gausman's four-seam generates above-average induced vertical break (IVB), but he lacks extension, so it doesn't matter. That's evident in how Gausman attacks left-handed hitters, where he throws it away from them, but it's not in the upper third of the zone often.

The results have been better via the four-seam against lefties in 2025 (.296 wOBA), though the .385 xwOBA says to be careful. For context, Gausman's four-seamer allowed a .348 wOBA (.359 xwOBA) in 2024 and a .317 wOBA (.366 xwOBA) in 2023 versus left-handed hitters.

Theoretically, Gausman could scrap the four-seam and throw more of another pitch, but the question is in favor of what? Unless it's a reliever, it doesn't make sense to pump mostly splitters or changeups because that's a risky approach, especially with the splitter being somewhat volatile.

Summary

Maybe it's a strong month from Gausman, but we've seen the skills jump closer to the previous peak seasons before 2024. That's evident in Gausman's 19 percent K-BB rate and the overall SwK at 13.1 percent. For three straight seasons before 2024, Gausman rocked a K-BB rate of 22-24 percent and a SwK of 13-16 percent. Typically, we examine more season-long usage and pitch movement changes. However, Gausman's splitter effectiveness has been something worth monitoring, and it's an actionable approach to bring it back to the prime seasons.

In Gausman's first June outing, he had the splitter working again, with a 20.4 percent SwK against the Athletics. However, the Athletics put the ball into play (53 percent hit rate), leading to an inefficient outing of 4.2 innings and 96 pitches.

What in the World is Happening with Zac Gallen?

Gallen's 4.37 xERA suggests better results, but that's not what many expected heading into 2025 after some ace-like seasons before 2024. So, what's happening with Gallen in 2025? It doesn't look like Gallen's pitch movement profiles have changed, with similar vertical and horizontal movement. The same goes with Gallen's top pitches via SwK, with the curveball (18.8 percent), changeup (13.4 percent), and slider (11.5 percent) leading the arsenal.

That's not far from the SwK numbers in 2024, though the changeup might be the most notable decline compared to his career averages. Gallen rocks a career SwK via the changeup at just under 16 percent, meaning the whiffs decline by 2-3 percentage points in 2024 and 2025.

Gallen's Changeup

Gallen threw the changeup as his third-most-used pitch against left-handed hitters, aligning with the recent seasons. Meanwhile, Gallen's changeup results (.237 wOBA) have typically been better than the expected metrics (.308 xwOBA) against left-handed hitters.

The movement profile for Gallen's changeup hardly shifted, all within an inch from previous seasons. Since most of the pitch-level data hasn't changed via the changeup, one would speculate on the locations. Gallen typically located the changeup low and away from left-handed hitters in 2023 and 2024. However, Gallen's changeup locations look slightly more sporadic in 2025.

Gallen has been throwing the changeup against left-handed hitters less often in the zone (36.7 percent) in 2025 compared to around 40-41 percent in previous seasons. Weirdly, left-handed hitters haven't been chasing the changeup with lower zone rates in 2025. That's evident in Gallen's changeup generating chases at a career-low rate (26.1 percent) in 2025 against lefties compared to 38-42 percent in the previous two seasons.

Interestingly, Gallen's changeup results have been better against left-handed hitters when thrown in the zone (.139 wOBA, .251 xwOBA) in 2025. For context, Gallen's changeup results in the zone were awful in 2024 (.377 wOBA, .357 xwOBA) and 2023 (.290 wOBA, .355 xwOBA). He seems to be trading whiffs for weak contact via the changeup against left-handed hitters. 

Meanwhile, Gallen's changeup results have been brutal when thrown outside the zone (.328 wOBA, .351 xwOBA) in 2025. That's much worse than the out-of-zone results via the changeup in 2024 (.175 wOBA, .250 xwOBA) and 2023 (.188 wOBA, .252 xwOBA). After a deep examination of the changeup, the results may regress toward previous seasons without any notable changes in 2025.

Summary

Gallen's control has been an issue, with a 38.6 percent ball rate in 2025 compared to a career rate of 36.5 percent. That's somewhat of an issue when Gallen boasts a 10.6 percent career swinging strike rate, not far from his 2025 SwK of 10.5 percent. If Gallen improves his control, we could see the results shift to past seasons. However, Gallen hasn't typically shown high-end stuff, evidenced by his pitch movement profiles. That likely tells us Gallen relied on his command, which he'll need to find since we haven't seen many glaring process changes in 2025.

Sandy Alcantara's Lower Arm Angle

Besides noticing Alcantara's lower arm angle, it's hard to look beyond his awful ERA (7.89), with a 4.68 xERA suggesting better results will come. The luck factors have been mostly to blame for Alcantara, but the skills took a step back in the early 2025 sample. That's evident in Alcantara's 5 percent strikeout minus walk rate and 9.4 percent swinging strike rate.

Let's figure out why and what's going on with Alcantara's arsenal. Alcantara showed a lower arm angle in spring training, mainly via a horizontal release point shifting closer to his midline. The release point changes maintained into the 2025 season, with his horizontal release moving 3.5 inches closer to his midline compared to 2024.

One might expect Alcantara's horizontal release point to affect the movement profiles. That's evident in Alcantara's horizontal movement profiles, via the sinker, changeup, and four-seam gaining arm-side fade. Meanwhile, Alcantara's pitches haven't made significant vertical movement profile changes in 2025.

Alcantara's changeup and four-seam added 2-3 inches of arm-side fade, with the sinker gaining nearly an inch. He typically had several pitches with above-average horizontal movement profiles, but they have been even better in 2025.

Alcantara's Approach Change to Left- and Right-Handed Hitters

Alcantara has been throwing more four-seamers to right-handed hitters, up to 22.9 percent usage compared to 14.7 percent (2023) and 17.5 percent (2022). The four-seam results have been worse in 2025 against righties, evidenced by a .362 wOBA (.342 xwOBA) versus a .363 wOBA (.343 xwOBA) in 2023.

The sinker (.273 wOBA, .286 xwOBA) and changeup (.221 wOBA, .280 xwOBA) have performed relatively well against right-handed hitters. One could argue whether Alcantara should lower the four-seam usage against right-handed hitters, especially if the results say to fade the fastball. Some of the locations have been slightly sporadic, but the sinker, four-seam, and changeup tend to move toward the inside part of the plate for right-handed hitters.

Alcantara's arsenal against lefties doesn't inspire confidence, with the curveball being his best pitch (.000 wOBA, .171 xwOBA), though it's his least-thrown offering. Meanwhile, Alcantara's four-seam (.457 wOBA), slider (.442 wOBA), and sinker (.420 wOBA) have been crushed by left-handed hitters, making us question the locations.

We'll highlight Alcantara's four-seam locations against left-handed hitters, especially since we've seen more of them thrown high and away from lefties in 2025. Left-handed hitters have been attacking the four-seam, especially in the zone. He found some success toward the inside corner of the plate against lefties, but that's not where he locates the four-seam.

Summary

We want to be patient when pitchers come off Tommy John surgery or any other significant injury. Outside of shallow leagues, there's likely not much to do other than bench and be patient unless injury news arises. If he doesn't make a notable adjustment to his approach against left-handed hitters, they will continue to destroy the four-seam, slider, and sinker.

Alcantara would benefit from reworking his slider and curveball, moving toward his glove side, since the fastballs and changeups fade toward his armside. The other fix involves Alcantara locating his gyro slider low and away from right-handed hitters or down and inside to lefties. He has been leaving the slider in the heart of the zone, leading to left-handed hitters smashing them (.442 wOBA, .635 xwOBA).

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