Mithrandir Metrics
Player Arizona Diamondbacks Refreshed Jun 16 06:00 AM ET
Player profile / Arizona Diamondbacks

Merrill Kelly

P profile with live context, projection links, and Mithrandir card history when available.

Cards
10
Modules
1
Live Δ
yes
Club Arizona Diamondbacks Position P Roster Active Status Healthy / active roster
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.

2026-06-16
15
Pitching
percentile
Pitching9 metrics
15
Arsenal7 metrics
42
Rolling projection

Preseason / current pace / Bayesian update

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

2026-06-16
ERA preseason4.22
ERA current pace5.46
ERA rolling p504.92
Observed weight56%
ERA
3.96 4.41 4.92 5.42 5.87
FIP
4.77 5.09 5.44 5.80 6.12
K%
14.0% 15.2% 16.6% 17.9% 19.2%
BB%
6.9% 7.7% 8.4% 9.2% 9.9%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-06-16
Pitching · percentile strip
WHIP1.54
15
ERA5.46
17
BB%9.4%
42 -24 vs proj
K%12.7%
2 -38 vs proj
xwOBA allowed0.403
1 -34 vs proj
Barrel allowed14.4%
1 -37 vs proj
Fastball velo91.9
15
Hard-hit allowed44.9%
15
Whiff%19.9%
25
Mithrandir+

Stuff+ and arsenal context

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

2026-06-16
Changeup Stuff+105
67
Fastball Stuff+99
25
Mithrandir Stuff+100
31
Curveball Stuff+103
72
Cutter Stuff+96
11
Sinker Stuff+102
46
Slider Stuff+100
40
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 Kelly, Merrill · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.314 0.403 2026-06-05: 0.4082026-06-06: 0.4142026-06-07: 0.4142026-06-08: 0.4142026-06-09: 0.4142026-06-10: 0.4142026-06-11: 0.4142026-06-12: 0.4142026-06-13: 0.4032026-06-14: 0.4032026-06-15: 0.4032026-06-16: 0.403 2026-06-05 2026-06-16 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 26%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 Kelly, Merrill · Aggregate zone metrics; not pitch-by-pitch locations Edge: 37%37%Zone: 43%43%Whiff: 20%20%Called strike: 14%14%First pitch strike: 48%48%Hard hit allowed: 45%45% 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 Kelly, Merrill · 2026 arsenal snapshot 4-Seam Fastball: 26.1%Changeup: 25.8%Cutter: 14.8%Slider: 12.2%Curveball: 11.3%Sinker: 9.6% FF26% · 92 mphprimary pitch FF 26%CH 26%FC 15%SL 12%CU 11%SI 10% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Kelly, Merrill · 2026 arsenal snapshot 15″30″45″60″ 4-Seam Fastball: 26% usage, 5″ horizontal break, 18″ drop, 91.9 mphFF92 mphChangeup: 26% usage, 9″ horizontal break, 35″ drop, 88.2 mphCH88 mphCutter: 15% usage, 2″ horizontal break, 20″ drop, 90.9 mphFC91 mphSlider: 12% usage, 1″ horizontal break, 33″ drop, 86.3 mphSL86 mphCurveball: 11% usage, 4″ horizontal break, 49″ drop, 82.0 mphCU82 mphSinker: 10% usage, 4″ horizontal break, 26″ drop, 92.2 mphSI92 mphPitch Out: 0% usage, 1″ horizontal break, 18″ drop, 90.3 mphPO90 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
FB 26.6% 250 99 qualified
CH 26.3% 247 105 qualified
FC 14.4% 135 96 limited sample
SL 13.0% 122 100 limited sample
CB 10.4% 98 103 limited sample
SI 9.4% 88 102 limited sample
Method note

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

Reference layer

Current snapshot

Age37
Height6' 2"
Weight202 lb
Debut2019-04-01
Live layer

Delta / regression

ERA Δ+1.09
K% Δ-0.084

positive regression

Regression watch

Unlucky so far. Better days ahead.

0.3σ gap
wOBA-against (actual)0.411
xwOBA-against (deserved)0.403

Kelly’s wOBA-against sits at 0.411, but the quality of contact underneath says it should be 0.403 — a gap of 0.009, 0.3 standard deviations from the MLB norm over 67 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
Pitching102026-05-254-Seam Fastball played up through FF/CU tunnel quality
Projection links / recent games

Available detail

Pitcher Projections 202621.0% K | 4.37 ERAProjection
2026-05-20 vs SF3 ER / 4 K6.0 IP
2026-04-14 @ BAL2 ER / 3 K5.1 IP