Mithrandir Metrics
Pitcher projection 2026 Refreshed Jun 1 06:00 AM ET
Pitcher projection / HOU · 2026

Arrighetti, Spencer

Run-prevention profile built on workable command

Primary
24.1% K%
Range
21.2% to 32.4%
Live Δ
yes
Team HOU Archetype Volatile contact Age 26 Status Healthy / active roster
Rolling projection

Preseason / current pace / Bayesian update

Rolling bands shrink current-season signal toward the preseason prior until the sample earns more weight.

2026-06-01
ERA preseason4.12
ERA current pace1.32
ERA rolling p502.85
Observed weight45%
ERA
1.57 2.18 2.85 3.53 4.14
FIP
2.88 3.35 3.87 4.39 4.85
K%
20.0% 21.6% 23.5% 25.3% 27.0%
BB%
8.9% 10.0% 11.2% 12.4% 13.4%
Current percentile strip

Actual percentile with projection tick

100th = best in MLB.

2026-06-01
Pitching · percentile strip
BB%13.1%
10 -25 vs proj
Barrel allowed5.8%
74 +34 vs proj
Fastball velo92.5
22
Hard-hit allowed29.8%
94
K%21.6%
46
Whiff%22.5%
46 -16 vs proj
xwOBA allowed0.339
27
Mithrandir+

Stuff+ and arsenal context

Stuff+ appears when the current pitch-event scoring artifact includes this pitcher; Arsenal Decomposition remains descriptive support under Stuff+.

2026-06-01
Mithrandir Stuff+101
42
Optimization map

Arsenal optimization map

Pitch-shape context from this pitcher’s current arsenal snapshot. Hover a pitch to inspect usage, movement, and bat-missing context.

6Pitches 2026Season 33%Top usage
ride armside gloveside +Arsenal gap +Shape contrast
Rolling form chart

xwOBA allowed snapshot line

Live snapshot series; true 50/100 PA windows require PA-level logs

12 snapshots
Mithrandir Metrics ROLLING XWOBA LINE Parameterized Mithrandir chart rendered as SVG for templates and exports. season=2026 Rolling xwOBA allowed Arrighetti, Spencer · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.314 2026-05-17: 0.3502026-05-19: 0.3502026-05-21: 0.3502026-05-23: 0.3452026-05-24: 0.3432026-05-25: 0.3432026-05-26: 0.3432026-05-28: 0.3432026-05-29: 0.3432026-05-30: 0.3392026-05-31: 0.3392026-06-01: 0.339 2026-05-17 2026-06-01 xwOBA allowed MITHRANDIR · CHARTS
Zone profile

Aggregate zone heatmap

Aggregate zone metrics from seasonal Statcast leaderboards.

Mithrandir Metrics ZONE HEATMAP Parameterized Mithrandir chart rendered as SVG for templates and exports. season=2026 Pitch Zone Profile Arrighetti, Spencer · Aggregate zone metrics; not pitch-by-pitch locations Edge: 36%36%Zone: 46%46%Whiff: 23%23%Called strike: 18%18%First pitch strike: 45%45%Hard hit allowed: 30%30% Dashed border = aggregate mixed-batter zone proxy MITHRANDIR · CHARTS
Pitch arsenal

Usage mix, movement map, and Stuff+ composition

2026 pitch-level arsenal aggregates; current season takes over after 100 tracked pitches across at least 2 pitch types. Descriptive pitch-type Stuff+ composition. Not a promoted predictive metric.

2026
Mithrandir Metrics PITCH ARSENAL DONUT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Arrighetti, Spencer · 2026 arsenal snapshot Curveball: 33.4%4-Seam Fastball: 30.0%Sweeper: 13.5%Sinker: 10.4%Changeup: 7.4%Cutter: 5.3% MIX CU 33%FF 30%ST 13%SI 10%CH 7%FC 5% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Arrighetti, Spencer · 2026 arsenal snapshot CU: HB 0.6, IVB 4.5CUFF: HB -0.3, IVB 1.5FFST: HB -0.3, IVB 3.5STSI: HB 0.7, IVB 2.0SICH: HB -1.1, IVB 3.0CHFC: HB 0.0, IVB 2.1FC horizontal break IVB MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
CB 32.0% 212 100 qualified
FB 30.2% 200 104 qualified
SL 14.5% 96 101 limited sample
SI 9.8% 65 103 limited sample
CH 7.7% 51 93 limited sample
FC 5.7% 38 110 limited sample
Method note

Renamed from the attempted Kirby Index after audit; true Kirby requires release-angle trajectory data.

Model read

Projection notes

1
templated note
Primary mix entering the season: 4-Seam Fastball 32%, Curveball 22%, Cutter 14%.
pitcher
Live context

Current-season signal

ERA Δ-2.97
K% Δ-0.025
Sample46.3 IP

negative regression

Projection table

Point projection and range

MetricPointRangeHalf-width
Innings68.7----
Batters Faced308----
K%24.1%21.2% to 32.4%+/- 5.6%
BB%9.8%6.5% to 13.0%+/- 3.2%
Whiff%24.4%20.7% to 31.6%+/- 5.4%
HR/91.450.59 to 1.91+/- 0.66
xwOBA Against0.3320.261 to 0.352+/- 0.045
Barrel% Allowed8.4%5.2% to 11.3%+/- 3.1%
ERA4.292.33 to 5.94+/- 1.81
FIP4.242.61 to 5.38+/- 1.39
WHIP1.3641.056 to 1.624+/- 0.284
Platoon / Shape
vs LHH

451 career BF

xwOBA0.303
K%26.5%
BB%11.8%
Barrel8.7%
vs RHH

390 career BF

xwOBA0.286
K%24.9%
BB%8.4%
Barrel7.3%