Mithrandir Metrics
Player Houston Astros Refreshed Jul 17 06:00 AM ET
Player profile / Houston Astros

Spencer Arrighetti

P · Bats/Throws R/R · 6' 2", 186 lb · Age 26

Cards
9
Modules
1
Live Δ
yes
Club Houston Astros Position P Roster Active Status Healthy / active roster
Traditional line

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
20247134.5329280145.01711.41
2025155.3577035.1311.42
2026754.501515082.0811.33
3 Seasons15234.6351500262.12831.38
At a glance

Season percentile report

The headline weighs outcome stats (xwOBA, barrels); each bar averages its full strip group below. 100 = best in MLB.

2026-07-17
33
Pitching
percentile
Pitching9 metrics
41
Arsenal7 metrics
55
Rolling projection

Preseason / current pace / Bayesian update

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

2026-07-17
ERA preseason4.12
ERA current pace4.50
ERA rolling p504.35
Observed weight60%
ERA
3.05 3.66 4.35 5.03 5.65
FIP
3.50 3.97 4.50 5.03 5.50
K%
20.8% 22.1% 23.6% 25.1% 26.5%
BB%
9.4% 10.3% 11.2% 12.2% 13.1%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-07-17
Pitching · percentile strip
WHIP1.36
44
ERA4.50
37
BB%12.3%
16 -18 vs proj
K%22.7%
51
xwOBA allowed0.349
16
Barrel allowed8.2%
41
Fastball velo92.3
20
Hard-hit allowed31.5%
92
Whiff%23.3%
53
Mithrandir+

Stuff+ and arsenal context

How nasty this pitcher's stuff grades in our pitch-level model. Missing coverage is shown explicitly.

2026-07-17
Curveball Stuff+101
35
Fastball Stuff+104
67
Mithrandir Stuff+102
53
Changeup Stuff+95
12
Cutter Stuff+113
99
Sinker Stuff+105
74
Slider Stuff+101
44
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 0.349 2026-07-06: 0.3342026-07-07: 0.3342026-07-08: 0.3342026-07-09: 0.3342026-07-10: 0.3492026-07-11: 0.3492026-07-12: 0.3492026-07-13: 0.3492026-07-14: 0.3492026-07-15: 0.3492026-07-16: 0.3492026-07-17: 0.349 2026-07-06 2026-07-17 xwOBA allowed MITHRANDIR · CHARTS
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.

7Pitches 2026Season 33%Top usage
ride armside gloveside +Arsenal gap +Shape contrast
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: 37%37%Zone: 45%45%Whiff: 23%23%Called strike: 17%17%First pitch strike: 45%45%Hard hit allowed: 32%32% 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.

Watch the pitches in 3D →

2026
Mithrandir Metrics PITCH ARSENAL DONUT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Arrighetti, Spencer · 2026 arsenal snapshot Curveball: 33.5%4-Seam Fastball: 28.9%Sweeper: 12.3%Sinker: 10.7%Changeup: 7.4%Cutter: 6.2% CU33% · 77 mphprimary pitch CU 33%FF 29%ST 12%SI 11%CH 7%FC 6% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Arrighetti, Spencer · 2026 arsenal snapshot 15″30″45″60″ Curveball: 33% usage, 7″ horizontal break, 53″ drop, 76.6 mphCU77 mph4-Seam Fastball: 29% usage, 3″ horizontal break, 18″ drop, 92.4 mphFF92 mphSweeper: 12% usage, 3″ horizontal break, 42″ drop, 79.4 mphST79 mphSinker: 11% usage, 8″ horizontal break, 23″ drop, 92.1 mphSI92 mphChangeup: 7% usage, 12″ horizontal break, 35″ drop, 84.2 mphCH84 mphCutter: 6% usage, 0″ horizontal break, 25″ drop, 87.5 mphFC87 mphSlider: 1% usage, 7″ horizontal break, 36″ drop, 82.2 mphSL82 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
CB 32.3% 273 101 qualified
FB 27.7% 234 104 qualified
SL 14.4% 122 101 limited sample
SI 9.5% 80 105 limited sample
CH 8.4% 71 95 limited sample
FC 7.7% 65 113 limited sample
Method note

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

Reference layer

Current snapshot

Age26
Height6' 2"
Weight186 lb
Debut2024-04-10
Live layer

Delta / regression

ERA Δ+0.21
K% Δ-0.014

negative regression

Regression watch

Running hot. Expect some cooling.

-0.8σ gap
wOBA-against (actual)0.327
xwOBA-against (deserved)0.349

Arrighetti’s wOBA-against sits at 0.327, but the quality of contact underneath says it should be 0.349 — a gap of 0.022, -0.8 standard deviations from the MLB norm over 80 IP. The results have outrun the underlying process; as the sample grows, expect the numbers to drift back toward the deserved level.

Mithrandir coverage

Module shelf

ModuleCardsLatestSignal
Pitching92026-07-08Stuff and strike quality carried the outing
Projection links / recent games

Available detail

Pitcher Projections 202624.1% K | 4.29 ERAProjection
2026-04-20 @ CLE2 ER / 3 K5.0 IP
2026-04-15 vs COL1 ER / 10 K6.0 IP