Mithrandir Metrics
Player Miami Marlins Refreshed Jun 14 06:00 AM ET
Player profile / Miami Marlins

William Kempner

P · Bats/Throws R/R · 6' 0", 222 lb · Age 24

Cards
0
Modules
0
Live Δ
--
Club Miami Marlins Position P Roster Active Status Healthy / active roster
Traditional line

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
2026100.005006.280.75
1 Seasons100.005006.280.75
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.

2026-06-14
82
Pitching
percentile
Arsenal3 metrics
82
Rolling projection

Preseason / current pace / Bayesian update

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

2026-06-14
ERA preseason4.05
ERA current pace0.00
ERA rolling p503.66
Observed weight9%
ERA
1.02 2.27 3.66 5.05 6.30
FIP
0.90 2.16 3.56 4.96 6.22
K%
8.1% 12.4% 17.2% 21.9% 26.2%
BB%
2.3% 4.2% 6.2% 8.3% 10.2%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-06-14
Mithrandir+

Stuff+ and arsenal context

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

2026-06-14
Fastball Stuff+104
68
Mithrandir Stuff+106
81
Slider Stuff+112
97
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.

4Pitches 2026Season 55%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: 44%44%Zone: 43%43%Whiff: 35%35%Called strike: 20%20%First pitch strike: 48%48%Hard hit allowed: 13%13% 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: 54.6%Sweeper: 22.7%Cutter: 13.4%Sinker: 9.3% FF55% · 95 mphprimary pitch FF 55%ST 23%FC 13%SI 9% 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: 55% usage, 0″ horizontal break, 19″ drop, 95.5 mphFF95 mphSweeper: 23% usage, 4″ horizontal break, 36″ drop, 81.6 mphST82 mphCutter: 13% usage, 0″ horizontal break, 30″ drop, 87.6 mphFC88 mphSinker: 9% usage, 6″ horizontal break, 28″ drop, 93.8 mphSI94 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
FB 57.1% 28 104 limited sample
SL 26.5% 13 112 limited sample
FC 10.2% 5 108 limited sample
SI 6.1% 3 70 limited sample
Method note

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

Reference layer

Current snapshot

Age24
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

Pitcher Projections 202618.2% K | 4.80 ERAProjection