Could a gyro pitch thrown at fastball speed work?

Abstract

In 2025 and 2026 no MLB pitcher-pitch average reached 93 mph while staying within 4 inches of zero in both induced vertical break (IVB) and horizontal break (HB), and the hardest gyro sliders averaged about 91 mph [1]. We propose a "bullet fastball", a near-pure gyro pitch thrown within about 4 mph of the four-seamer, which our calibrated model places about 15.6 inches below a 98 mph riding fastball [2]. Free-flight measurements by Lyu, Kensrud and Smith (2020) show that a gyro ball's drag depends on seam orientation (drag coefficient 0.29 versus 0.37) [3], which the model translates into about 1.9 mph of plate speed. A shape model predicts about 30% whiff, but the main unknown is biomechanical, whether gyro spin can be produced without losing the velocity that defines the pitch.

1. Motivation and gap

Our analysis of 5,102 pitcher-pitch-seasons found no pitch-type average at 93 mph or more with |IVB| and |HB| both at 4 inches or less [1]. At 95 mph or more there are three averages within 8 inches in both directions, Jacob Misiorowski's 2026 cutter (95.8 mph, 7.2 inches IVB, 1.4 glove side), Grant Taylor's 2025 cutter (95.3, 6.4, 3.0 glove side) and Camilo Doval's 2025 sinker (96.6, 5.2, 7.4 arm side). A first pass of our analysis stated that no 95 mph pitch moved this little, which was incorrect. The hardest gyro sliders averaged 91.4 mph (Yovanny Cruz, 2026), 91.3 (Chase Petty, 2025) and 90.7 (George Klassen, 2026), at 14% to 17% active spin [1].

Hard gyro shapes perform well. Driveline's Travis Sawchik defines a "vertical slider" as a gyro-dominant breaking ball within 10 mph of the fastball with 4 inches or less of HB, and reports that it has had the highest whiff rate of any breaking-ball shape every year since 2015 while accounting for only about 1% of pitches (0.66% in 2015, 1.21% in 2026) [4]. Logan Gilbert's slider moved from 83.5 mph with 4.2 and 6.4 inches of break in 2021 to an 88.7 mph bullet with 0.3 and 0.8 in 2023 [5], and Langin reports that Kona Takahashi added an 87.7 mph near-zero gyro in NPB, about 5.3 mph above the league's right-handed gyro average [6]. Jack Lambert notes that adding approach angles to Driveline's Stuff+ raised grades for low-efficiency pitches such as gyro sliders, whose value break alone does not capture [7]. The gap is velocity. Across the movement plot, each extra inch of break has so far cost speed [1], and a bullet fastball tests whether the near-zero point can be pushed to fastball velocity.

2. Physical basis

2.1 Gyro spin and the Magnus force

Only the spin component perpendicular to the velocity produces a Magnus force. Nathan writes spin efficiency as ε = |ω̂ × v̂|, the transverse share of the spin [8]. A pitch whose axis points at the plate spins like a thrown football. Lyu, Kensrud and Smith measured lift coefficients of 0.01 and -0.01 for gyro spin in two-seam and four-seam orientations, against 0.17 and 0.18 for backspin [3]. A pure gyro pitch therefore falls under gravity and drag alone. Its reported IVB is not exactly zero, because Statcast movement removes only gravity, and drag acting on the downward component of velocity adds an apparent lift that Nathan estimated at about 1.7 inches on average in 2012 PITCHf/x data [9].

F_M ∝ C_L(S),   S = Rωε / v   ⇒   ε → 0 gives F_M → 0R ball radius, ω total spin, v speed. Pure gyro removes the Magnus term, not the drag term.

2.2 Drag depends on the gyro face

Drag scales as F_D = ½ρAC_Dv². Lyu, Kensrud and Smith fired nine baseballs four times in each orientation at 35.8 m/s (about 80 mph) and 1,500 rpm. Gyro spin in a two-seam orientation gave the lowest drag coefficient, 0.29, and gyro spin in a four-seam orientation the highest, 0.37, while backspin drag was 0.33 and 0.32 for the two orientations. Backspin drag correlated with seam height (R² 0.72 for four-seam), but gyro drag did not (R² below 0.1) [3]. Drag was sensitive to seam orientation for gyro spin but not for backspin.

A plausible explanation, which is our inference, is that a gyro ball keeps the same face toward the flow while it spins about the flight axis, so it behaves more like a non-spinning ball whose drag depends on which seams lead. Smith and Sciacchitano (2022) found that non-spinning balls had their lowest drag near 0 and 90 degrees of rotation about the four-seam axis and their highest near 45 degrees, with the flow attached to about 130 degrees at the low-drag orientation against about 100 degrees at 45 degrees [10]. The seams act as trips that move separation, as a trip wire does on a sphere [11]. Adair had conjectured that a two-seam fastball should show more drag than a four-seam one [12], and the free-flight data show nearly equal backspin drag and the opposite ordering for gyro spin.

2.3 Two smaller effects

Because the spin vector stays fixed in space while the path bends, part of the gyro spin becomes transverse spin during flight. David Kagan described this for gyro pitches in 2017 [13]. At 94 mph the path turns only a few degrees, and in our run efficiency rises from 0.10 at release to about 0.19 at the plate. Second, gyro spin is the condition under which a seam patch can hold one side of the ball and produce a seam-shifted wake [14]. We modelled no seam force for this pitch, so any real SSW, of unknown sign, would add scatter or a bias we have not simulated.

3. Simulated shape

Each pitch was integrated with a fourth-order Runge-Kutta scheme using Nathan's pitched-ball coefficients, a fixed spin vector and an air density of 1.194 kg/m³, calibrated against 2025 Savant pitcher averages [15][2]. The two gyro faces use the measured drag coefficients, 0.29 and 0.37, in place of the default drag model. Inputs are a right-handed pitcher at a 40 degree arm angle, 94 mph, 2,300 rpm and 10% efficiency, paired with a 98 mph four-seamer.

The bullet finishes with about 15.6 inches less ride than the four-seamer. Choosing the low-drag face brings it to the plate 1.9 mph faster than the high-drag face and about 4 to 5 milliseconds earlier, with roughly 0.3 inches less drop. When each pitch is aimed through the four-seamer's position at the Baseball Prospectus tunnel point, 23.8 feet from the plate [16], the two-seam-face bullet finishes 7.4 inches lower and 5.1 inches glove side of the four-seamer (9.0 inches in total), 14 milliseconds later. When the bullet and the 88 mph gyro slider are aimed at the same spot, they are only 1.5 inches apart at the tunnel point, and the bullet arrives 28 milliseconds sooner [2]. The bullet's steep approach angle, -6.26 degrees against -4.69 for the four-seamer, reflects the absence of lift.

The figure runs the same model in your browser and draws both gyro faces. This design has no seam-shifted wake slider, because the seam effect we simulate acts through drag rather than a side force. With the tunnel box ticked, every pitch passes through the four-seamer's tunnel point, so the catcher's view shows the divergence after the swing decision. Untick it to aim each pitch at the middle of the zone. Slow motion replays the flight at a quarter of real speed, which makes the two faces' small difference in arrival easier to see, and the movement plot shows how empty the region near zero is at this velocity. Live values can differ from the table by about 0.1 unit, and approach angles change with the aiming mode.

Any sense that the bullet "drops off the table" late is perceptual. Its separation from the four-seamer grows with the square of time, and Bahill and Baldwin show how a batter's misjudged prediction of a pitch's fall produces the impression of a sudden break on a smooth path [17].

4. Expected effectiveness

Our gradient-boosting shape model (velocity, IVB, HB, arm angle, extension and differences from the primary fastball; five-fold cross-validation grouped by pitcher) explains 56% of out-of-sample variance in whiff rate (RMSE 6.6 points) and 24% in xwOBA (RMSE 0.058) [2]. It predicts 29.7% whiff and a .286 xwOBA for both faces, against league baselines of 21.6% and .339 for four-seamers, 22.6% and .348 for cutters and 33.3% and .289 for sliders. The two faces score the same because the model uses release velocity and movement, not plate speed, so the drag lever is invisible to it.

The region is thin. One real pitcher-pitch row lies within one distance unit and 70 within two, so the prediction partly extrapolates in velocity. The nearest similar shapes are Calvin Faucher's 2025 cutter (92.1 mph, 2.0 inches IVB, 3.7 glove side, 18.7% whiff, .344 xwOBA over 386 pitches), Yovanny Cruz's 2026 slider (91.4, 2.2, 1.0 glove side, 33.3% whiff, .324 over 126) and Daniel Espino's 2026 slider (92.0, 4.0, 3.6 glove side, 27.9%, .292 over 79) [2][1]. The nearly 15-point spread between Faucher's cutter and Cruz's slider at nearly the same shape is a reminder that arsenal context and usage matter as much as shape.

The timing effect of the drag lever is small. Baseball Prospectus reported a league-average flight-time difference of 26 milliseconds between pitch pairs [16], against 4 to 5 milliseconds between the two gyro faces. The main hypothesised value is instead the vertical separation from a 98 mph riding fastball at only about 4 mph less velocity, a larger vertical gap than a hitter usually sees at that speed difference.

5. Complementary pitches and sequencing

The bullet's natural partner is a riding four-seamer at the top of the zone, in the same speed band with about 15 inches of vertical separation, so that the bullet finishes under the same swing plane. A splitter (89 mph, 7.3 inches IVB, 9.3 arm side in our arsenal) works below and arm side, and a sweeper supplies the horizontal dimension. Tyler Zombro of Tread Athletics recommends gyro sliders for vertical-profile pitchers and sweepers for east-west pitchers [18], and Mario Delgado Genzor describes the "pronator's triangle" of fastball, changeup and gyro slider [19]. The bullet fits the same logic at higher speed.

6. Execution

Grip and arm action

Hold the ball at fastball depth with the fingers shifted to the outer (thumb-side) third, so the fingertip shear acts on the side of the ball, and orient the grip so the seams run parallel to the flight path in the low-drag two-seam gyro face. The cue is to "throw a spiral" with full fastball arm speed, no wrist turn, staying behind the ball. Zombro advises throwing gyro sliders harder than sweepers and checking bullet spin with phone slow motion [18], and Langin showed one slider grip moving between sweeper and gyro shapes on the cue alone [20]. The working target is within about 4 mph of the four-seamer. At 8 to 9 mph slower, the pitch has become a gyro slider.

What anatomy permits and what it costs

Jinji, Sakurai and Hirano (2011) showed that the spin axis lies in the plane of the palm and fingers just before release [21]. If that hand plane contains the line of flight, the fingers shear the side of the ball and the spin vector points toward the plate, which is how gyro arises. Kinoshita and colleagues (2017) measured index and middle finger forces of about 97 newtons on a four-seamer, with combined shear peaking 4 to 5 milliseconds before release as the source of backspin [22]. The bullet redirects that shear rather than removing it. Delgado Genzor notes that pronators throw gyro sliders easily because "you don't really need to supinate very well" [19].

The likely cost is speed. Matsuo and colleagues (2024) found that the ball leaves the hand 8 to 12 m/s faster than the hand itself, partly through finger flexion at release [23]. Shifting the fingers to the side may shorten that final lever, which is our proposed explanation for why gyro pitches have so far been slower than fastballs. On load, slider kinematics differ from the fastball in only 2 of 26 parameters (Escamilla et al. 1998) [24], and professional fastballs and sliders carried 8% to 9% more varus torque than changeups (Escamilla et al. 2017) [25]. A pitch thrown at fastball effort should be counted as a fastball for workload. Lyman and colleagues (2002) linked sliders to more elbow pain in 9 to 14 year olds [26], an epidemiological association with possible confounding, and this design is not intended for youth pitchers. For learning, Rob Gray's constraints-led approach suggests defining the target by its outcome (efficiency, movement and velocity gap) and using ball-flight data as feedback [27].

7. How to test it

• Throw the bullet and the four-seamer in the same session and record release speed, spin, efficiency and movement with Rapsodo, TrackMan or Hawk-Eye.
• Film from behind at 1,000 frames per second or more to confirm the gyro face, and compare spin-based and observed axes to detect any seam force (Nathan 2023; Driveline 2020) [28][29].
• Throw at least 30 pitches per face. Where plate or zone speed is available, compare the faces at matched release speed.
• Judge shape over dozens of repetitions and value over hundreds of pitches [30].

Success criteria follow from the definition. Efficiency should stay below about 20%, |IVB| and |HB| within 4 inches, and the velocity gap to the four-seamer within about 4 mph. The drag prediction is a plate-speed advantage of roughly 2 mph for the two-seam face at matched release speed. A gap that settles near 8 mph means the pitch is a gyro slider, and no plate-speed difference between faces would mean the 80 mph drag result does not carry to game speed.

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8. Limitations and open questions

• Velocity feasibility. No pitcher has yet averaged this shape above about 91 mph, and the main uncertainty is human, not aerodynamic.
• Drag extrapolation. The 0.29 and 0.37 coefficients come from nine balls at about 80 mph and 1,500 rpm [3]. Seam effects depend on Reynolds number, and Utah State found that some separation modes disappear near 92 mph sea-level equivalent [31].
• Unmodelled seam force. A gyro face may produce a seam-shifted wake of unknown size and sign.
• Model limits. The shape model explains about half of whiff variance and cannot value plate speed.
• Command and adaptation. The pitch has no command data, and hitters adapt to new shapes, as the sweeper's declining whiff rate shows.

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References

1. Baseball Savant, MLB Advanced Media. Statcast search exports grouped by pitcher and pitch type, plus the spin-direction and active-spin leaderboards, 2025 and 2026 regular seasons (2026 season to date). Retrieved October 2026 and analysed by the author (5,102 pitcher-pitch-seasons with at least 50 pitches). https://baseballsavant.mlb.com/statcast_search
2. Osnacz A (2026). Pitch AI new-pitch trajectory and shape models: RK4 integration of Nathan's pitched-ball coefficients calibrated to 2025 Baseball Savant pitcher averages, and a gradient-boosting shape model of whiff% and xwOBA (5-fold cross-validation grouped by pitcher; whiff R² 0.56, RMSE 6.6 points; xwOBA R² 0.24, RMSE 0.058). Unpublished analysis, October 2026. Method summary in New pitch types from first principles.
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10. Smith BL, Sciacchitano A (2022). Baseball drag measurements in free flight. Applied Sciences 12(3), 1416. https://doi.org/10.3390/app12031416
11. Anderson JD, Cadou CP (2023). Fundamentals of Aerodynamics, 7th edition. McGraw Hill. Section 6.6, The flow over a sphere, the real case, pp. 513-515 (Figures 6.9 and 6.10).
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16. Long J, Judge J, Pavlidis H (2017). Introducing Pitch Tunnels. Baseball Prospectus, January 24, 2017. https://www.baseballprospectus.com/news/article/31030/prospectus-feature-introducing-pitch-tunnels/
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20. Driveline Baseball (Langin C) (2022). How to Throw a Slider: Thumb Positions, Grips, and Cues. YouTube, March 24, 2022. https://www.youtube.com/watch?v=XwJ4oV6jBnM
21. Jinji T, Sakurai S, Hirano Y (2011). Factors determining the spin axis of a pitched fastball in baseball. Journal of Sports Sciences 29(7), 761-767. https://doi.org/10.1080/02640414.2011.553963
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27. Gray R (2021). How We Learn to Move: A Revolution in the Way We Coach & Practice Sports Skills. Perception Action Consulting & Education. Chapter 7 (constraints-led approach and transition feedback), chapter 8 (differential learning), chapter 14 (representative practice).
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29. Driveline Baseball (Aucoin D, Caravan A, eds.) (2020). More than what it seams: An introduction to seam-shifted wakes and their effect on sinkers. Driveline Baseball, November 1, 2020. https://www.drivelinebaseball.com/2020/11/more-than-what-it-seams-an-introduction-to-seam-shifted-wakes-and-their-effect-on-sinkers/
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31. Smith BL (2022). Effect of velocity or altitude on seam shifted wake, part 3 of 4 (Post 74). Baseball Aerodynamics, Utah State University, April 28, 2022. https://www.baseballaero.com/2022/04/28/effect-of-velocity-or-altitude-on-seam-shifted-wake-part-3-of-4-post-74/

Related reading

• New pitch types from first principlesThe hub. Methods, the gap map and all six proposals.
• The pole-seam riserA low-slot four-seam that rides like a higher slot.
• The float cutterA riding cutter in the mid 80s.
• Mirror sweepersOne spin, two breaks, set by seam orientation.
• The reverse hammerAn arm-side 12-6 curveball for the empty corner of the plot.
• The two-face splitterOne split grip, two lifts.
• How to throw a sliderGyro and sweeping slider grips.
• What is Stuff+?How shape and velocity get graded.