Mithrandir Metrics
Player Boston Red Sox Refreshed Jul 19 06:00 AM ET
Player profile / Boston Red Sox

Justin Slaten

P · Bats/Throws R/R · 6' 4", 222 lb · Age 28

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

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
2024622.93440255.1581.01
2025244.24360334.0251.09
2026145.40270023.1321.50
3 Seasons9103.8310705112.21151.14
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.

2026-07-19
59
Pitching
percentile
Pitching9 metrics
55
Arsenal4 metrics
74
Rolling projection

Preseason / current pace / Bayesian update

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

2026-07-19
ERA preseason3.74
ERA current pace5.64
ERA rolling p504.36
Observed weight33%
ERA
2.84 3.56 4.36 5.16 5.88
FIP
2.81 3.19 3.61 4.02 4.40
K%
19.1% 21.7% 24.5% 27.4% 29.9%
BB%
4.7% 6.0% 7.3% 8.7% 9.9%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-07-19
Pitching · percentile strip
WHIP1.46
24
ERA5.64
15
BB%6.9%
78
K%29.3%
91 +43 vs proj
xwOBA allowed0.274
86 +34 vs proj
Barrel allowed8.1%
44 -19 vs proj
Fastball velo96.7
82
Hard-hit allowed43.2%
23
Whiff%22.7%
47 -17 vs proj
Mithrandir+

Stuff+ and arsenal context

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

2026-07-19
Cutter Stuff+106
88
Fastball Stuff+108
88
Mithrandir Stuff+107
87
Slider Stuff+99
32
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 Slaten, Justin · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.314 0.274 2026-07-08: 0.2862026-07-09: 0.2802026-07-10: 0.2802026-07-11: 0.2752026-07-12: 0.2752026-07-13: 0.2772026-07-14: 0.2772026-07-15: 0.2772026-07-16: 0.2772026-07-17: 0.2772026-07-18: 0.2772026-07-19: 0.274 2026-07-08 2026-07-19 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.

6Pitches 2026Season 44%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 Slaten, Justin · Aggregate zone metrics; not pitch-by-pitch locations Edge: 36%36%Zone: 53%53%Whiff: 23%23%Called strike: 17%17%First pitch strike: 49%49%Hard hit allowed: 43%43% 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 Slaten, Justin · 2026 arsenal snapshot Cutter: 44.2%4-Seam Fastball: 26.2%Sweeper: 17.4%Sinker: 9.0%Curveball: 3.0%Split-Finger: 0.2% FC44% · 93 mphprimary pitch FC 44%FF 26%ST 17%SI 9%CU 3%FS 0% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Slaten, Justin · 2026 arsenal snapshot 15″30″45″60″ Cutter: 44% usage, 0″ horizontal break, 23″ drop, 93.2 mphFC93 mph4-Seam Fastball: 26% usage, 0″ horizontal break, 12″ drop, 96.5 mphFF97 mphSweeper: 17% usage, 4″ horizontal break, 35″ drop, 85.9 mphST86 mphSinker: 9% usage, 7″ horizontal break, 14″ drop, 97.2 mphSI97 mphCurveball: 3% usage, 6″ horizontal break, 52″ drop, 84.4 mphCU84 mphSplit-Finger: 0% usage, 13″ horizontal break, 32″ drop, 87.6 mphFS88 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
FC 46.5% 105 106 limited sample
FB 30.1% 68 108 limited sample
SL 15.9% 36 99 limited sample
SI 4.0% 9 95 limited sample
CB 3.5% 8 101 limited sample
Method note

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

Reference layer

Current snapshot

Age28
Height6' 4"
Weight222 lb
Debut2024-03-30
Live layer

Delta / regression

ERA Δ+1.85
K% Δ+0.071
Mithrandir coverage

Module shelf

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

Available detail

Pitcher Projections 202622.2% K | 3.79 ERAProjection
2026-04-04 vs SD0 ER / 1 K1.0 IP
2026-04-03 vs SD0 ER / 1 K1.0 IP
2026-03-26 @ CIN0 ER / 2 K1.0 IP