Fantasy Baseball Starting Pitcher Arsenal Changes for Week 16: Pitch Mix, Velocity, Movement (2025)

July 10, 2025

Corbin's fantasy baseball starting pitcher breakouts, risers, and sleepers for Week 16 of 2025 displaying changes in their pitch mix, movement, and velocity.

Welcome back, RotoBallers, to my weekly "Starting Pitcher Arsenal Changes" article series for Week 16 of the 2025 fantasy baseball season. We researched 33 starting pitchers, with three more in this column, including two young arms with upside. Today's article will discuss a few starting pitchers who made actionable adjustments, such as a release point change or a new pitch, as well as location changes, and whether these adjustments will 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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George Kirby's Lower Arm Angle

Kirby has been throwing from a lower arm angle, a 6-7 degree decline compared to 2023 and 2024. That's mainly because Kirby lowered his vertical release point by nearly two inches (1.9). Meanwhile, Kirby's horizontal release moved by almost 3.5 inches farther away from his midline compared to 2023, yet it was similar to 2024.

Kirby's splitter dropped 1-2 inches fewer over the past two seasons. However, the splitter faded two inches more often toward his arm side. Since Kirby introduced the splitter in 2023, the results against left-handed hitters have declined. That's evident in Kirby's splitter allowing a .113 wOBA (.189 xwOBA) in 2023, .318 wOBA (.314 xwOBA) in 2024, then a .444 wOBA (.511 xwOBA) in 2025.

Besides Kirby's splitter movement profile changing, the curveball dropped 2-3 inches more in 2025. That's partly because Kirby has been throwing the curveball 1-2 mph harder in each of the past two seasons. Theoretically, Kirby throwing a harder curveball would lead to less vertical movement. As one would expect, Kirby's curveball locations haven't been as precise in 2025 against left-handed hitters after dealing with the injury.

Left-handed hitters have been attacking the knuckle curve when Kirby throws in the zone. That's evident in Kirby's knuckle curve, resulting in a .391 wOBA (.402 xwOBA) in 2025 against left-handed hitters. For context, those numbers are worse than his knuckle curve outcomes against left-handed hitters when thrown in the zone in 2024 (.320 wOBA, .202 xwOBA).

Kirby lowered his zone rate on the knuckle curve, throwing it 33.7 percent of the time, down from 42.4 percent (2024) and 64.7 percent (2023). Unsurprisingly, Kirby's knuckle curve has been consistently effective when thrown outside the zone against lefties, evidenced by a .254 wOBA (.203 xwOBA) and a 22.8 percent swinging strike rate in 2025. That's similar to the career results against the knuckle curve outside the zone, with a .219 wOBA (.212 xwOBA) and a 16.4 percent swinging strike rate.

Kirby's Slider is Sweeping More

Speaking of breaking pitches, Kirby's slider is sweeping more in 2025 with the change in release points and arm angles. Kirby's slider maintained his velocity and vertical movement, but added three inches of arm-side sweep in 2025. That's likely due to the arm angle changes by Kirby, leading to more side-to-side movement.

Kirby's slider has been effective against right-handed hitters, allowing a .259 wOBA (.271 xwOBA) in 2025. That's similar to Kirby's slider results against righties in 2024 (.191 wOBA, .259 xwOBA) and 2023 (.252 wOBA, .264 xwOBA). However, Kirby's slider results against left-handed hitters have been brutal, allowing a .467 wOBA (.328 xwOBA) as one of his worst pitches.

One might speculate that the slider locations are related to his arm angle changes and injury recovery. Kirby threw his slider over 24 percent of the low and inside to left-handed hitters in 2024, significantly less than in 2025 (36.7 percent). Like the knuckle curve, when Kirby threw the slider in the zone, we saw poor results in 2025.

That's evident in Kirby's slider, allowing a .541 wOBA (.350 xwOBA), his career-worst outcomes when thrown in the zone against left-handed hitters. Kirby has been a command and location artist, with the second-highest Location+ over the past three seasons (2023-25) behind Pablo López among qualified starting pitchers. López, Kirby, and Logan Gilbert were the only three starters with a Location+ of 110 or higher across the past three seasons.

Summary

Kirby's 3.59 xERA has been over one run better than his actual ERA. That suggests Kirby's skills hint at better outcomes, evidenced by his 18 percent K-BB rate, 32 percent ball rate, and 10.2 percent swinging strike rate. For context, Kirby's strikeout skill metrics align with his career K-BB percentage (20 percent) and swinging strike rate (11.2 percent). It might be a bumpy ride if Kirby maintains his lower arm angle since it's impacting his pitch movement profiles. Buy low on Kirby where possible.

Edward Cabrera's Changeup Added Arm-Side Movement

Cabrera's changeup has been thrown relatively hard, with a velocity of around 93-94 mph. His changeup added over one inch of arm-side movement in 2025 compared to 2024 and 2023. Meanwhile, Cabrera's changeup also dropped over two inches of vertical movement, making it somewhat of a slightly slower sinker.

Cabrera's changeup has been one of his better pitches against left-handed hitters. His changeup allows a .259 wOBA (.283 xwOBA) in 2025 against lefties, with the curveball being his best one, evidenced by the .175 wOBA (.189 xwOBA). He has been locating the changeup low and away to left-handed hitters in 2025, which is slightly different from his changeup locations in 2024.

Cabrera throws his changeup low and away from lefties 35 percent of the time in 2025, slightly higher than in 2024 (31 percent). Unsurprisingly, Cabrera's results have been deadly when he locates it low and away from left-handed hitters. That's evident in Cabrera's changeup, allowing a .231 wOBA in 2025 and a .108 wOBA in 2024 when he threw it low and away from left-handed hitters.

The results have been positive when Cabrera locates the changeup low and away from left-handed hitters. Sometimes, when a pitcher has a different movement profile, it might be related to their release points. That said, Cabrera has been throwing from a lower arm angle.

Cabrera's Lower Arm Angle

Cabrera lowered his vertical release point by over 1.5 inches, with over a one-inch difference in his horizontal release in 2025. That indicates Cabrera lowered his release point and shifted it closer to his midline when compared to 2023, but similar to 2024. We've seen Cabrera's overall pitches add over three inches of downward movement, with a similar horizontal movement profile to 2024.

That's mainly because Cabrera's curveball was the only pitch to add horizontal movement, with his other pitches losing side-to-side action. For context, Cabrera's curveball gained nearly three inches of glove-side sweep. The curveball has been an effective pitch against left- and right-handed hitters in 2025, which was better than in past seasons.

Cabrera's curveball allowed a .175 wOBA (.189 xwOBA) against left-handed hitters, with a .235 wOBA (.181 xwOBA) versus righties in 2025. That's been better than the curveball results against lefties (.324 wOBA, .292 xwOBA) and righties (.265 wOBA, .306 xwOBA) in 2024. Besides the curveball movement profile difference, one would guess there might be location differences.

Cabrera threw his curveball low and away from right-handed hitters 28.3 percent of the time, leading to a .123 wOBA. That's similar to his pitch percentage in 2025, throwing it 31.1 percent of the time, low and away, resulting in a .148 wOBA. Cabrera's stuff has typically been in the high-end range, so there will be times when the command can be shaky.

Summary

Cabrera has the best xERA of his career (3.66), aligning with his actual ERA (3.33). He has shown slightly better control, with a 37 percent ball rate in 2025, compared to his career ball rate of 39 percent. Cabrera's arm angle change could be related to the location and command, evidenced by a career-best Location+ (100), four points above his career norm. Buy into Cabrera's arsenal changes since they coincide with the release points and locations.

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