Fantasy Baseball Starting Pitcher Arsenal Changes: Pitch Mix, Velocity, and Movement (Week 6)

Corbin examines three fantasy baseball pitcher risers and sleepers displaying changes in their pitch mix, movement, and velocity heading into Week 6 (2024).

Welcome back to the weekly column, where we cover a few starting pitchers and their arsenal changes via pitch mix, velocity, and movement. Last week's article examined Michael King, Ryan Feltner, and Ronel Blanco. This week, we're examining two deep-league starting pitchers who might be underrated based on their skills and early-season success.

We're at a point where the pitch movement, arsenal, and velocity should tell us a story with a handful of starts under their belts. With more injuries likely coming soon, we'll want to continue identifying streaming pitcher skills or struggling pitchers with underlying metrics suggesting better results coming soon.

After examining the changes for these starting pitchers in the early parts of the 2024 season, we'll summarize whether we should act or be patient with the data. Again, we have a small sample of five starts or so in 2024, so it could be legitimate or noisy by the end of the month. Reach out to me on X if you have a pitcher you have questions about that may be included in a future article.

A New Version of Spencer Turnbull

With the Phillies, Spencer Turnbull added a sweeper, which he throws 29.3 percent of the time, as his second-most used pitch. The sweeper has generated the second-most swings and misses (14.1 percent) with quality results, given the .169 wOBA. Turnbull's curveball has the best swinging-strike rate in his arsenal at 24.8 percent, over double his career average (12.1 percent). 

The sweeper gives Turnbull a quality offering against same-handed hitters, evidenced by a .137 wOBA in 2024. Besides the sinker, Turnbull struggled to find a consistent pitch to attack right-handed hitters. Turnbull's sweeper generates a decent chunk of called strikes as he locates it lower in the zone, evidenced in his previous start against the Reds on April 24.

In Turnbull's start against the Reds, the sweeper garnered eight called strikes, translating into a 43 percent called strike plus whiff rate (CSW%). He has been locating the sweeper down and away. In past seasons, we've seen Turnbull's slider perform well when he located it down and away from right-handed hitters, with 2021 as evidence given the 17.9 percent swinging strike rate. 

It's a small sample in 2024, but it appears like a concerted effort by Turnbull to locate the breaking balls down and away from right-handed hitters. The sweeper gives him another version of the slider with more glove-side movement.

Let's revisit the curveball because it's been nearly unhittable against left-handed hitters in 2024. Though some luck factors have been in his favor, evidenced by a .250 BABIP (2024) compared to a career BABIP of .413, the curveball still possesses a juicy movement profile. That indicates the curveball should generate more whiffs and weak contact, as it's doing in 2024.

Turnbull's curveball most notably added 1-2 inches of sweep while adding a few inches of vertical movement in 2024. That aligns with the swinging-strike rate gains and the near-elite results with a .100 wOBA and .078 xwOBA in 2024. There will likely be regression on the curveball results with the career wOBA (.311) and xwOBA (.252). However, we're witnessing a new version of Turnbull with the Phillies. 

Summary

The overall profile for Turnbull doesn't indicate tons of upside, but he made a couple of noticeable changes by adding a sweeper plus movement profile adjustments to the curve. There have been rumors of Turnbull going to the bullpen once Taijuan Walker returns. Walker looked shaky in his debut outing, and we're optimistic about Turnbull sticking in the rotation. It's hard to imagine Turnbull losing his rotation spot based on the positive changes and success early in 2024, though it's possible. With an underwhelming four-seamer, given the below-average Induced Vertical Break (IVB), he'll need the sweeper and curveball to complement his arsenal. Turnbull moved from a deep-league streamer to a semi-reliable option based on the arsenal changes, so hold and enjoy until we see more concerns pop up.

Dean Kremer Has a Better Four-Seamer

Dean Kremer's 10-strikeout performance against the Angels last week caught my attention. It led me to notice 10 whiffs on the four-seamer, translating to a 21.3 percent swinging strike rate. It's probably a bit noisy since he posted an eight percent swinging strike rate overall on the four-seamer, with a career average of 9.7 percent. Part of Kremer's four-seamer success related to his location of throwing it in the upper third of the zone.

Against the Angels, nine of Kremer's 10 four-seamer whiffs came in the upper third of the zone. That's helpful since Kremer's four-seamer improved from a movement profile standpoint. In 2021 and 2022, Kremer's four-seamer had over 16.5 inches of IVB. However, his four-seamer added over one inch of IVB on the four-seamer, with the main change being his horizontal release point being slightly closer to the midline of his body.

That indicates Kremer's four-seamer goes from an average to above-average fastball, though the results haven't been great, with a .451 wOBA in 2024. With the poor batted ball results, Kremer's mediocre swinging-strike rate on the four-seamer is unsurprising in 2024. Theoretically, Kremer's four-seamer should elicit more whiffs and weak contact. Unfortunately, last Wednesday's start against the Angels seems to be an outlier, with zero whiffs on the four-seamer against the Yankees on Tuesday, April 30.

Kremer Added a Splitter

Besides the four-seamer changes, Kremer added a splitter, which he threw 13.7 percent of the time. The batted ball results have been positive, with a .186 wOBA overall and a .314 wOBA against left-handed hitters. Interestingly, the splitter has performed as his best pitch for whiffs, with a 15.8 percent swinging strike rate.

Kremer swapped his changeup for a splitter, but the movement profiles suggest he should use the changeup instead. However, the changeup lost vertical movement in 2023. It's somewhat of a mixed bag since the changeup swinging strike rate (10.1 percent) and .338 wOBA against lefties hasn't inspired confidence.

The Cutter Has Evolved

Kremer's cutter evolved in 2024 by adding over three inches of vertical movement and not as much glove-side sweep. It seems Kremer's cutter turned into a "harder" slider that he uses at a career-high mark of 38.8 percent against right-handed hitters. He tends to locate the cutter down and away from right-handed hitters to induce weaker contact while not generating enough whiffs (11.3 percent swinging strike rate).

That's a positive movement profile change for his cutter, with early positive results against right-handed hitters in 2024 (.199 wOBA) compared to 2023 (.285 wOBA). However, it might be fluky to begin the season since Kremer's .327 xwOBA on the cutter against right-handed hitters hints at worse results.

Summary

The skills have never excited us for Kremer, with a career swinging strike rate of 9.7 percent and the 2024 numbers looking similar at nine percent. He controls the zone with decent walk and ball rates (35.5 percent). Theoretically, Kremer's four-seamer changes into an above-average fastball that should generate better results. There's a scenario where he continues to locate the fastball up in the zone while eliciting enough swings and misses on the cutter and splitter. However, Kremer doesn't possess tons of strikeout upside, so he profiles more as a deep-league streamer. 

Luis Gil is Throwing More Changeups

Admittedly, I'm biased against Luis Gil based on his brutal control. That's evident in Gil's 40.2 percent ball rate. The control issues will lead him to struggle with being inefficient. In 2024, Gil ranks 23rd in pitches per start (94). Gil is one of the only pitchers averaging under five innings per start (4.9) besides Sean Manaea and Ryan Weathers among starters averaging above 90 pitches per game.

We're used to Gil as a four-seamer and slider pitcher, but he has been throwing more changeups in 2024. He throws the changeup 23.5 percent of the time, as his second-most used offering after a 6-7 percent usage in previous seasons. Gil's changeup gives him an effective offering against both sides of the plate, allowing a .170 wOBA against right-handed hitters and .149 wOBA versus lefties. 

It's been most helpful against right-handed hitters because he lacked a quality offering to limit the damage. Interestingly, Gil's changeup lost two mph of velocity yet added 2-3 inches of drop and an inch of arm-side fade. Though it's still not an above-average pitch from a movement profile, Gil's changeup adjustments have been translating into positive results.

Gil's changeup elicited a 12 percent swinging-strike rate against the Brewers on April 26. The changeup trailed the four-seamer (17.4 percent) and slider (19.2 percent) in swinging-strike rate, though all three pitches performed better than his season-long and career averages.

Gil's Improved Four-Seam

Unfortunately, Gil's changeup will remain inconsistent, so expect more reliability on the four-seamer and slider. It's worth noting Gil's four-seamer improved by moving into the above-average range of IVB at 18.2 inches, with an inch more of arm-side fade. 

Gil's horizontal release point seems to be impacting his IVB by using a slightly more three-quarters release moving away from the midline. That aligns with the horizontal and vertical movement changes in 2024, which backs up Gil's fastball grading as his best pitch. Theoretically, Gil's four-seamer should generate more whiffs, and he seems to be commanding it decently in the upper third of the zone. 

Summary

Expect peaks and valleys for Gil because the xERA hints at regression shifting away from his favor. The control issues will hinder the consistency similar to pitchers like Edward Cabrera, though Gil doesn't have the ceiling of Cabrera yet. We love the improved four-seamer. However, his arsenal needs more consistency from the slider and changeup. That's especially true for the slider, as it lost over four inches of vertical movement and six inches of sweep, translating to a career-worst swinging-strike rate and wOBA allowed. 

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