Can a seam loop make a mid-80s cutter float?

This is one of six proposed designs; the shared methods are in Can physics invent new pitches? Throughout, we assume a right-handed pitcher and use IVB for induced vertical break and HB for horizontal break, positive to the arm side (so cut is negative). Movement runs from release to the plate as on Baseball Savant, and spin tilt is a clock face from the pitcher's view.

1. Motivation and gap

In Travis Sawchik's 2025 Driveline survey of missing pitches, Zach Bove, the Royals' director of pitching strategy, described a "float cutter" with more turn than a cutter and vertical rise, "maybe a mid-80s pitch," a blend of a riding sweeper and a regular cutter [2]. Lance Brozdowski's 2026 analysis named a neighbouring region "Corbin Burnes territory," too much sweep for a cutter and too much lift for a slider, and called it largely unaccessed [4].

Statcast data support both descriptions. Among 2025 and 2026 pitcher-pitch-seasons with at least 50 pitches, 19 rows from 14 pitchers sat at 82 to 88 mph with at least 8 inches of IVB and 3 to 12 inches of glove-side break [1]. Only one non-fastball thrown at 88 mph or less (excluding a 74 mph submarine slider) averaged 12 or more inches of IVB with at least 4 inches of cut, Tobias Myers's 2026 cutter at 86.6 mph, 12.2 IVB and 5.2 inches of cut from a 62 degree slot. Taijuan Walker's 2025 cutter (87.1 mph, 12.7 IVB, 3.0 inches of cut) and Tyler Anderson's 2025 cutter (84.4 mph, 13.3 IVB, 1.7 inches of cut) ride but barely cut. High-ride cutters of any speed are rare as well. Only 5 of 466 cutter rows reached 15 inches of IVB [1], close to Driveline's mid-September 2025 count of 2 such cutters in 267 [2]. In the movement-direction frontier, the fastest glove-side-and-ride pitch with 12 to 16 inches of total break was 89.2 mph [1].

The gap may matter, since cutters are where seam effects pay. In Tom Tango's analysis reported by Nicklaus Gaut, cutters in the top quartile of seam-shifted wake were worth −0.61 runs per 100 pitches against +0.58 for the bottom quartile [5], and Chris Langin's Driveline classification found that the sweeping cutter, whose glove-side movement comes largely from non-Magnus force, had the best Stuff+ of the cutter profiles [6]. There is also a reason for caution. Tread Athletics' Tyler Zombro advises keeping a whiff-oriented cutter at about 10 inches of IVB or less and above about 84 to 85 mph [7]. The float cutter deliberately breaks the first rule and sits close to the second.

2. Physical basis

2.1 What gyro spin does and does not do

A cutter spins partly like a bullet. Its mean Statcast active spin in 2025 and 2026 was 47% (10th to 90th percentile 30% to 62%) [1], so about half its spin points along the flight path. That gyro component makes essentially no Magnus force; in free flight, Lyu, Kensrud and Smith (2020) measured lift coefficients of about 0.01 and −0.01 for two-seam and four-seam gyro orientations [8]. Only the transverse component, set by the hand plane at release (Jinji, Sakurai and Hirano 2011), produces Magnus movement [9].

Gyro matters for a different reason. The seam-shifted wake (SSW) arises when a seam near the hemisphere plane makes the boundary layer on its side separate earlier; the wake leaves off-center toward that side and the ball is pushed the other way [10][11]. Seams act as trips that promote transition, as Bertin and Cummings note for baseball seams and as Anderson and Cadou illustrate with a trip-wire hoop on a sphere [12][13]. To produce a net force, a seam patch must stay on one side of the ball near the separation line for most of each rotation [11]. Smith and Nathan both conclude that real SSW pitches need some gyro, and Mikey Ajeto's 2022 analysis argues that gyro lets a seam patch sit stably near the separation line on one side [14][15]. Smith also showed that the best seam orientation for SSW shifts with the amount of gyro [16][17]. Statcast data are consistent with this. 28% of cutter pitcher-seasons (130 of 463) showed axis deviations of 30 degrees or more, against 0.2% of four-seamers [1].

2.2 The Looper as the laboratory anchor

Utah State's "Looper" held one seam loop on one side of a 90 mph, 1,200 rpm pitch and produced about 4 inches of vertical and 4 inches of horizontal seam-driven movement, with the two 180 degree mirror orientations differing by about 8 inches [18]. Its break pointed about 45 degrees from the spin-axis direction, away from the loop side [19]. Separation was non-deterministic from throw to throw in later particle image velocimetry work (Smith et al. 2024) [20]. The design inference is simple. A loop held low, along the bottom of the ball, should make the air separate earlier underneath, shift the wake downward and push the ball up.

Two cautions apply. The Looper was a high-efficiency pitch at half the spin of a typical cutter, so its magnitude does not transfer directly to a 2,400 rpm, 50% efficient cutter. And which seam patch stays steady on a gyro-heavy axis depends on the exact orientation [16]. We assume, rather than demonstrate, that a loop placed low under the cutter's axis can produce an upward push of 2 to 5 inches.

2.3 Model

We integrate the pitched-ball equation of motion with Nathan's drag and lift coefficients and add the seam force as a side-force coefficient C_S pointing toward 12:00 [21][3].

a = −K C_D v v + K C_L v² m̂ + K C_S v² ŝ − g ẑ

Over a 52.6 ft flight, one inch of seam-driven movement corresponds to C_S of about 0.0112 [3]. We simulate C_S 0.025 (LOW, about 2.2 inches), 0.04 (MID, 3.6 inches) and 0.055 (HIGH, 4.9 inches). For reference, the Looper corresponds to roughly 0.05 to 0.06 and MLB sinkers to roughly 0.07 to 0.10 [18][14].

3. Simulated shape

The model pitcher is right-handed with a 40 degree arm angle. The float cutter is thrown at 86 mph with 2,400 rpm, 50% efficiency and an 11:00 tilt, plus the upward seam force [3]. Pitches in the table are aimed at the middle of the zone.

Source: Pitch AI trajectory model [3]. Release speeds shown; the float cutter reaches the plate at 79.2 mph.

At MID the float cutter has 3.8 inches more ride and 2.9 inches more cut than the standard cutter in the same arsenal, at 3.5 mph less. It sits at the edge of the observed population rather than inside it. When aimed through the four-seamer's position 23.8 ft from the plate, Baseball Prospectus's tunnel point [22], it finishes about 6.6 inches to the glove side and 4.1 inches below the four-seamer (3.5 to 4.6 inches across cases, 7.5 to 8.1 inches of total separation) and arrives 38 ms later. Its VAA of about −5.75 degrees at mid-zone is steeper than the four-seamer's −4.87, because it is slower, but flatter than the standard cutter's −5.84 despite being 3.5 mph slower.

The interactive figure runs the same model in your browser. The catcher's view plays the pitches in real time (tick slow motion for a 4x replay) and the side and top views show the paths. The slider sets the seam-force coefficient; the shaded band is the LOW to HIGH range, and zero leaves a slow, partly gyro cutter with about 9 inches of ride. With the tunnel box ticked, every pitch passes through the four-seamer's point 23.8 ft from the plate, so the catcher's view shows only the separation that develops afterwards; untick it to aim each pitch at the middle of the zone, as in the table. The movement panel places the simulated pitch on the real 2025 to 2026 Statcast cloud, where it lands in a sparse band between the cutter and sweeper clusters.

4. Expected effectiveness

Our descriptive gradient-boosting model of whiff rate and xwOBA, trained on 5,036 pitcher-pitch-seasons with velocity, IVB, HB, arm angle, extension and differences from the primary fastball as inputs, explained 56% of whiff variance (RMSE 6.6 points) and 24% of xwOBA variance (RMSE .058) in five-fold cross-validation grouped by pitcher [3].

Distance is scaled in velocity (3 mph), IVB (3 in), HB (3 in) and arm angle (10 degrees). League values are pitch-weighted. Source: [3].

Read literally, the model predicts about ten whiff points above an average cutter. We do not think that number should be taken at face value. With at most two real pitcher-seasons within distance 1, the tree model is extrapolating, and tree models answer extrapolation with the value of the nearest populated region. The nearest real shapes performed far below the prediction. Taijuan Walker's 2025 cutter (87.1 mph, 12.7 IVB, 3.0 inches of cut, 40.1 degrees) had a 19.5% whiff rate and .320 xwOBA over 621 pitches, and his 2026 version 17.1% and .434 over 84; Aaron Civale's 2026 cutter (88.1 mph, 10.1 IVB, 6.0 inches of cut) had 24.7% and .289 over 717; Nestor Cortes's 2025 cutter (86.7 mph, 11.3, 4.8) had 21.6% and .362; and Ian Seymour's 2026 slider (83.2 mph, 12.2, 3.4) had 28.6% and .290 [3][1]. These are similar shapes, not users of this design. Our reading is that the prediction is driven mainly by the pitch's differences from its fastball (8.5 mph slower and 15.3 inches less arm-side movement), which resemble a slider's, more than by its raw shape. That is an inference about the model, not a finding about hitters.

The plausible mechanism of value is timing and expectation. The pitch shares the four-seamer's ride direction while arriving 38 ms later, compared with Baseball Prospectus's league-average flight-time difference of 26 ms between consecutive pitches [22]. Bahill and Baldwin's account of batters' perceptual errors emphasizes how speed misjudgments translate into apparent rise or drop [23]. The ride is not a late force; displacement under a roughly constant force grows with the square of time, which concentrates the visible difference near the plate [24].

5. Complementary pitches and sequencing

• Riding four-seam. The natural partner. Same ride direction, 8.5 mph slower; 4.5 inches apart at the tunnel point when both are aimed mid-zone, well under the 10.0 inch league average reported by Baseball Prospectus [22][3]. A timing pitch that tunnels with the heater.
• Sweeper. The same glove-side family with about 13 inches more drop and 7.5 inches more sweep, 3.5 mph slower, 4.3 inches apart at the tunnel point and 19 ms later [3]. In Jack Lambert's Mix+ and Match+ framing described by Sawchik, the float cutter and four-seamer form a matched pair and the sweeper adds a distinct one [2].
• Sinker or changeup. An arm-side pitch so the hitter cannot cheat to the glove side.
• Standard cutter. Probably redundant. The two are only 0.7 inches apart at the tunnel point [3]; the float cutter would replace it rather than join it.

A reasonable sequencing hypothesis is four-seam and float cutter at the top of the zone in alternation, sweeper below and away, and the arm-side pitch to keep the plate wide. Gaut's report of Tango's quartiles suggests seam-shifted cutters are valuable against both hands, but we have no matchup-specific evidence for this shape [5].

6. Execution

Grip. Start from a two-seam cutter interface. Tread Athletics' coaches recommend the two-seam orientation as the starting point for pitches meant to move with seams, and Brian Bannister suggests marking the ball so the orientation can be checked on slow-motion video [25][26]. Rotate the ball so one horseshoe loop runs along the bottom of the ball under the thumb side, and set the ball slightly deeper in the hand than a normal cutter. The deeper grip is where we expect the roughly 3 mph velocity drop to come from. Matsuo et al. (2024) found the ball leaving 8 to 12 m/s faster than the hand, partly because of late finger flexion, and a deeper ball plausibly shortens that final lever [27].

Arm action. Fastball intent with a cutter hand, fingers behind and slightly outside the ball so the hand plane is mildly supinated and efficiency lands near 45% to 55%. Some coaches cue the index finger to finish the ball; on the hand-plane rule this biases the axis toward cut, though finger release order rests on a single 1980 dissertation [9][28]. Cutter and slider kinematics are nearly identical to the fastball, with 2 of 26 parameters differing in Escamilla et al. (1998) [29]. Driveline's Chris Langin found that cues can matter more than grips for these pitches; the same grip moved from sweeper to gyro by cue alone [30].

What anatomy permits and what it costs. Mild supination around release is natural. Matsuo et al. (2016) found a brief supination phase near release in all 20 pitchers they filmed at 1,000 Hz [31], and forearm rotation occurs entirely at the radio-ulnar joints [32]. Breaking-ball hand orientation is pre-set before release rather than twisted at release (Sakurai et al. 1993) [33]. Loads for sliders and cutters are fastball-like (Escamilla et al. 2017; Fleisig et al. 2006, whose slider sample was small) [34][35], and Hall cites elbow valgus torques of as much as 64 N·m in pitching [36]. The specific cost to watch is effort. Solomito et al. (2018) found that a larger forearm supination moment went with a larger elbow varus moment, while forearm position itself did not [37]. The cue should be to set the hand, not to drive supination. A pitch at 86 mph from fastball intent should carry slightly lower loads than the four-seamer, since loads rise with ball speed [36], but no study has measured this grip.

Learning. Rob Gray's constraints-led approach would define the float cutter by its outcome (a target box on the movement plot, a velocity window and an efficiency window) and let the athlete search, with the movement plot as feedback and small random variations in loop position and grip depth to encourage exploration [38]. Pitch AI's Pitch Lab can import TrackMan or Rapsodo CSV files and show the movement profile and pitch design recommendations, which is the feedback loop this needs; it does not measure seam orientation.

7. How to test it

1. Instruments. A pitching machine or athletes, a camera at 1,000 frames per second or more behind the release to confirm the loop position, and tracking of both the spin-based axis (Rapsodo) and observed movement (TrackMan or Hawk-Eye). The difference between them isolates the seam force (Nathan 2023; Driveline 2020) [14][39]. Langin notes that some of the best cutters show an arm-side spin-based axis but glove-side movement, which only movement-based tracking reveals [40].
2. Built-in control. Throw the loop-low version and the loop-high mirror at the same effort. If the mechanism works, loop-low should ride and loop-high should sink, as the Looper's flipped orientations did [18]. Use 30 or more throws per orientation, because separation is non-deterministic [20].
3. Windows. Keep only throws at 45% to 55% efficiency and record velocity, because the design fails if it drifts into slider speed [7].
4. Prediction. At MID, observed IVB 3 to 4 inches above what the spin-based axis implies, with cut roughly unchanged [3].
5. Value. Shape stabilizes within dozens of repetitions; outcomes need hundreds of pitches (Premier Pitching Performance 2026) [41].

8. Limitations and open questions

• Gyro and seam interplay. No measurement exists of a low loop on a 2,400 rpm, 50% efficient cutter. The Looper was tested near 1,200 rpm and high efficiency [18], and the optimal orientation shifts with gyro [17].
• Magnitude and sign. We assume a 2 to 5 inch upward push. A different loop position could push sideways or down, and shot-to-shot variation is large [20].
• Velocity. The design assumes a 3.5 mph drop from a deeper grip. If it falls further it becomes a riding slider, a shape Zombro's guidance suggests is weaker [7].
• Outcome model. The 32% whiff prediction is an extrapolation with almost no nearby data, and the closest real shapes whiffed 17% to 29% [3].
• Labels. Statcast pitch types are classifier outputs, not grips, so the gap counts depend on the cutter and slider labels [1].
• Feasibility. No athlete has thrown this design under measurement and no load data exist for the grip.

The float cutter has the largest potential value in this series and one of the larger uncertainties. The decisive experiment is cheap, a loop-low versus loop-high comparison on a cutter at the intended efficiency. If the two separate by several inches in the predicted direction, the pitch is worth building; if they do not, the gap stays empty for a physical reason.

Frequently asked questions

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Pitch AI's Pitch Lab turns your TrackMan or Rapsodo data into a movement profile, estimates your arm angle and recommends which pitch to develop next. Its grip library videos cover the cutter grips this design starts from.

References

1. Baseball Savant, MLB Advanced Media. Statcast search exports grouped by pitcher and pitch type (2025 season and 2026 season to date) and the spin-direction and active-spin leaderboards; pitcher-pitch-seasons with at least 50 pitches (5,102 rows, 915 pitchers, 1,371,201 pitches); retrieved and summarized by Pitch AI, October 2026. https://baseballsavant.mlb.com/statcast_search
2. Sawchik T (2025). The search for missing pitches. Driveline Baseball, September 22, 2025. https://www.drivelinebaseball.com/2025/09/the-search-for-missing-pitches-has-pitch-design-given-the-game-all-the-shapes-it-needs-or-are-we-at-the-end-of-the-beginning/
3. Pitch AI (2026). New-pitch trajectory simulations and descriptive shape model: RK4 integration of the Nathan pitched-ball model with a seam-shifted wake side-force term, calibrated to 2025 Statcast pitcher averages, and a gradient-boosting model of whiff rate and xwOBA on 2025 to 2026 pitch shapes with 5-fold cross-validation grouped by pitcher. Internal analysis, October 28, 2026; methods described in Can physics invent new pitches?
4. Brozdowski L (2026). The Sweeper is Dead. YouTube, February 13, 2026. https://www.youtube.com/watch?v=ndnV6RNZcR0
5. Gaut N (2021). Ride the Seam-Shifted Wake. FanGraphs, April 16, 2021 (reports Tom Tango's cutter run values by seam-shifted wake quartile). https://fantasy.fangraphs.com/ride-the-seam-shifted-wake/
6. Langin C, Driveline Baseball (2022). How to Identify Baseball Pitches: Cutter. YouTube, May 7, 2022. https://www.youtube.com/watch?v=uDsDpaVb158
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12. Bertin JJ, Cummings RM (2022). Aerodynamics for Engineers, 6th ed. Cambridge University Press. Ch. 3, pp. 132 to 135 (seams on a baseball and dimples on a golf ball as transition-promoting roughness); ch. 5, pp. 258 to 260 (forward movement of a roughness strip raising minimum drag).
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15. Ajeto M (2022). We're Talking About Seam-Shifted Wake Wrong. Baseball Prospectus, May 17, 2022. https://www.baseballprospectus.com/?p=74601
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18. Smith BL (2020). A zero-gyro seam-shifted wake pitch, the Looper (Post 49). Baseball Aerodynamics (baseballaero.com), Utah State University, February 17, 2020. https://www.baseballaero.com/2020/02/17/a-zero-gyro-seam-shifted-wake-pitch-the-looper-post-49/
19. Smith BL (2020). How to use the Looper and Scuffball (Post 50). Baseball Aerodynamics (baseballaero.com), Utah State University, February 27, 2020. https://www.baseballaero.com/2020/02/27/how-to-use-the-looper-and-scuffball-post-50/
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22. 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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39. 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/
40. Langin C, Driveline Baseball (2022). How to Throw a Cutter: Thumb Positions, Grips, and Cues. YouTube, May 12, 2022. https://www.youtube.com/watch?v=jlkqclvn6zg
41. Premier Pitching Performance (2026). The Pitch Design Phase in Baseball: Developmental Fit, Workload-Informed Timing, Biomechanical Determinants of Effectiveness, and Evidence-Based Evaluation Thresholds. February 2, 2026. https://premierpitching.com/blogs/premier-pitching-chronicles/the-pitch-design-phase-in-baseball-developmental-fit-workload-informed-timing-biomechanical-determinants-of-effectiveness-and-evidence-based-evaluation-thresholds

Related reading

• Can physics invent new pitches?The overview, methods and all six proposed designs.
• The pole-seam riserA proposed low-slot four-seam that gets ride back from a seam.
• Mirror sweepersOne spin, two breaks, from flipping the seams.
• The bullet fastballA proposed gyro pitch at fastball speed.
• How to throw a cutterThe standard grips this design starts from.