Mithrandir Metrics
Player Miami Marlins Refreshed Sep 1 06:00 AM ET
Player profile / Miami Marlins

William Kempner

P · Bats/Throws R/R · 6' 0", 222 lb · Age 25

Cards
0
Modules
0
Live Δ
--
Club Miami Marlins Position P Roster Current MLB team Status IL-60
Traditional line

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
2026102.9290012.1140.97
1 Seasons102.9290012.1140.97
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.

2026-09-01
56
Pitching
percentile
Arsenal4 metrics
56
Rolling projection

Preseason / current pace / Bayesian update

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

Pending

Rolling player projection appears after current-season Statcast and projection joins refresh.

Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-09-01
Mithrandir+

Stuff+ and arsenal context

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

2026-09-01
Fastball Stuff+104
61
Mithrandir Stuff+105
77
Sinker Stuff+95
10
Slider Stuff+105
76
Rolling form chart

xwOBA allowed snapshot line

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

0 snapshots
No chart yet

No Live State xwOBA snapshots are available for this player.

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.

5Pitches 2026Season 48%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 Kempner, William · Aggregate zone metrics; not pitch-by-pitch locations Edge: 38%38%Zone: 45%45%Whiff: 31%31%Called strike: 18%18%First pitch strike: 52%52%Hard hit allowed: 23%23% 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 Kempner, William · 2026 arsenal snapshot 4-Seam Fastball: 48.2%Sweeper: 22.1%Sinker: 14.6%Cutter: 12.6%Changeup: 2.5% FF48% · 95 mphprimary pitch FF 48%ST 22%SI 15%FC 13%CH 3% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Kempner, William · 2026 arsenal snapshot 12″24″36″48″ 4-Seam Fastball: 48% usage, 5″ horizontal break, 18″ drop, 95.5 mphFF95 mphSweeper: 22% usage, 10″ horizontal break, 36″ drop, 81.6 mphST82 mphSinker: 15% usage, 2″ horizontal break, 27″ drop, 94.0 mphSI94 mphCutter: 13% usage, 1″ horizontal break, 30″ drop, 87.3 mphFC87 mphChangeup: 3% usage, 12″ horizontal break, 40″ drop, 86.8 mphCH87 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
FB 47.6% 39 104 limited sample
SL 26.8% 22 105 limited sample
SI 12.2% 10 95 limited sample
FC 9.8% 8 116 limited sample
CH 3.7% 3 93 limited sample
Method note

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

Reference layer

Current snapshot

Age25
Height6' 0"
Weight222 lb
Debut2026-05-05
Live layer

Delta / regression

No Live State delta is available for this profile yet.

Mithrandir coverage

Module shelf

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

Available detail

No projection links or recent game log rows are available yet.