Split-FingerArsenal Shape: Armside Drop
Δ HB +0.6in · Δ VB -10.9in
Current: HB 6.4in / VB +8.9in
Recommended: HB 7.0in / VB -2.0in
Optimization diagnostic / LAA
Yusei Kikuchi
Yusei Kikuchi's tools (57) outpace production (54) by 3 points. Primary finding: existing split-finger is present, but its movement shape does not currently cover the desired armside-drop window. Also flagged: Arsenal Shape: Gloveside Sweep; Usage Underuse: Curveball. Most actionable fix: reshape existing split-finger to add armside drop rather than developing a new pitch from scratch.
Data window 2026-08-17 / 2026-08-31Confidence HIGH
Optimization map
Arsenal shape map
Hover each pitch to inspect current usage, movement shape, and whiff context beside the written diagnosis.
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armside
gloveside
Movement reshape
Pitch movement dual-view
Current shape against the recommended movement window. Animation starts when this section scrolls into view.
SliderArsenal Shape: Gloveside Sweep
Δ HB -8.2in · Δ VB +0.6in
Current: HB -0.8in / VB +1.4in
Recommended: HB -9.0in / VB +2.0in
Diagnosis
Fixable gaps
| Signal | Cause | Fix | Confidence |
|---|---|---|---|
| Stuff-to-Whiff Gap (Command)0.15 | Elite stuff tunnels well but pitches land in hittable zones | Reduce heart-of-zone pitches; increase edge and chase attemptsBetter location could push whiff rate toward 24%+ | MEDIUM |
| Arsenal Shape: Armside Drop0.85 | Existing Split-Finger is present, but its movement shape does not currently cover the desired armside-drop window. | Reshape existing Split-Finger to add armside drop rather than developing a new pitch from scratch.Shape refinement would improve platoon coverage while preserving the existing usage signal. | HIGH |
| Arsenal Shape: Gloveside Sweep0.70 | Existing Slider is present, but its movement shape does not currently cover the desired gloveside-sweep window. | Reshape existing Slider to add gloveside sweep rather than developing a new pitch from scratch.Shape refinement would improve platoon coverage while preserving the existing usage signal. | HIGH |
| Usage Underuse: Curveball0.70 | Curveball grades as the best pitch (whiff 25.4%, CSW 32.8%) but is only thrown 16.0% of the time | Increase Curveball usage to at least league-average for that pitch typeUsage rebalancing is the simplest optimization with immediate impact | MEDIUM |
| Usage Overuse: 4-Seam Fastball0.60 | 4-Seam Fastball grades as the weakest pitch (whiff 18.7%, CSW 23.5%) but is thrown 52.6% of the time | Reduce 4-Seam Fastball usage in favor of higher-performing offeringsUsage rebalancing is the simplest optimization with immediate impact | MEDIUM |
Arsenal / metrics
Underlying components
| Component | Usage | Velo | Whiff |
|---|---|---|---|
| 4-Seam FastballFF | 53% | 95.7 | 18.7% |
| SliderSL | 21% | 87.0 | 22.3% |
| CurveballCU | 16% | 77.9 | 25.4% |
| Split-FingerFS | 13% | 86.1 | 24.7% |
| CutterFC | 5% | 94.6 | 0.0% |