Mithrandir Metrics
Player Boston Red Sox Refreshed Sep 28 06:00 AM ET
Player profile / Boston Red Sox

Aroldis Chapman

P · Bats/Throws L/L · 6' 4", 235 lb · Age 38

Cards
0
Modules
0
Live Δ
yes
Club Boston Red Sox Position P Roster Current MLB team Status Healthy / active roster
Traditional line

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
2024553.796801461.2981.35
2025531.176703261.1850.70
2026341.925303551.2711.12
17 Seasons63522.489160402873.014021.08
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.

2026-09-28
78
Pitching
percentile
Pitching9 metrics
75
Arsenal4 metrics
80
Rolling projection

Preseason / current pace / Bayesian update

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

2026-09-28
ERA preseason3.48
ERA current pace1.92
ERA rolling p502.72
Observed weight49%
ERA
1.20 1.92 2.72 3.52 4.24
FIP
1.90 2.35 2.85 3.35 3.81
K%
29.4% 31.6% 33.9% 36.3% 38.4%
BB%
8.0% 9.2% 10.6% 12.0% 13.3%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-09-28
Pitching · percentile strip
WHIP1.20
73
ERA1.92
97
BB%10.9%
27
K%33.2%
97
xwOBA allowed0.252
96
Barrel allowed7.1%
56 +20 vs proj
Fastball velo97.4
91
Hard-hit allowed37.8%
55
Whiff%27.2%
82
Mithrandir+

Stuff+ and arsenal context

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

2026-09-28
Fastball Stuff+106
77
Mithrandir Stuff+108
95
Sinker Stuff+110
96
Slider Stuff+102
52
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 Chapman, Aroldis · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.313 0.252 2026-09-14: 0.2562026-09-18: 0.2562026-09-19: 0.2562026-09-20: 0.2562026-09-21: 0.2562026-09-22: 0.2562026-09-23: 0.2562026-09-24: 0.2532026-09-25: 0.2532026-09-26: 0.2522026-09-27: 0.2522026-09-28: 0.252 2026-09-14 2026-09-28 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.

4Pitches 2026Season 37%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 Chapman, Aroldis · Aggregate zone metrics; not pitch-by-pitch locations Edge: 38%38%Zone: 49%49%Whiff: 27%27%Called strike: 15%15%First pitch strike: 52%52%Hard hit allowed: 38%38% 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 Chapman, Aroldis · 2026 arsenal snapshot 4-Seam Fastball: 37.3%Sinker: 31.6%Slider: 18.6%Split-Finger: 12.5% FF37% · 97 mphprimary pitch FF 37%SI 32%SL 19%FS 12% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Chapman, Aroldis · 2026 arsenal snapshot 9″18″27″36″ 4-Seam Fastball: 37% usage, 1″ horizontal break, 11″ drop, 96.9 mphFF97 mphSinker: 32% usage, 5″ horizontal break, 12″ drop, 98.0 mphSI98 mphSlider: 19% usage, 1″ horizontal break, 32″ drop, 85.9 mphSL86 mphSplit-Finger: 12% usage, 4″ horizontal break, 31″ drop, 90.0 mphFS90 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
FB 42.5% 203 106 qualified
SI 37.4% 179 110 limited sample
SL 20.1% 96 102 limited sample
Method note

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

Reference layer

Current snapshot

Age38
Height6' 4"
Weight235 lb
Debut2010-08-31
Live layer

Delta / regression

ERA Δ-1.33
K% Δ-0.010

positive regression

Regression watch

Unlucky so far. Better days ahead.

1.8σ gap
wOBA-against (actual)0.311
xwOBA-against (deserved)0.252

Chapman’s wOBA-against sits at 0.311, but the quality of contact underneath says it should be 0.252 — a gap of 0.058, 1.8 standard deviations from the MLB norm over 54 IP. The results have been worse than the process deserves; as the sample grows, expect the numbers to climb back toward the underlying level.

Mithrandir coverage

Module shelf

ModuleCardsLatestSignal
No Mithrandir card history is available for this player yet.
Projection links / recent games

Available detail

Pitcher Projections 202634.2% K | 3.25 ERAProjection
2026-08-15 @ PIT0 ER / 2 K1.0 IP
2026-05-20 @ KC0 ER / 1 K1.0 IP
2026-04-20 vs DET0 ER / 1 K0.2 IP
2026-04-17 vs DET0 ER / 1 K1.0 IP
2026-04-14 @ MIN0 ER / 3 K1.0 IP