Mithrandir Metrics
Player St. Louis Cardinals Refreshed Jun 12 06:00 AM ET
Player profile / St. Louis Cardinals

JoJo Romero

P · Bats/Throws L/L · 5' 11", 215 lb · Age 29

Cards
0
Modules
0
Live Δ
yes
Club St. Louis Cardinals Position P Roster Active Status Healthy / active roster
Traditional line

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
2024733.36650159.0511.15
2025462.07650861.0551.25
2026023.48310031.0311.19
7 Seasons15133.54228012223.22141.23
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.

2026-06-12
54
Pitching
percentile
Pitching9 metrics
48
Arsenal5 metrics
52
Rolling projection

Preseason / current pace / Bayesian update

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

2026-06-12
ERA preseason3.63
ERA current pace3.54
ERA rolling p503.60
Observed weight35%
ERA
2.07 2.79 3.60 4.41 5.14
FIP
1.69 2.53 3.48 4.42 5.27
K%
19.0% 21.2% 23.5% 25.9% 28.0%
BB%
5.6% 6.9% 8.3% 9.8% 11.1%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-06-12
Pitching · percentile strip
WHIP1.18
69
ERA3.54
54
BB%8.4%
54
K%25.2%
68 +20 vs proj
xwOBA allowed0.341
24 -31 vs proj
Barrel allowed6.0%
72 +22 vs proj
Fastball velo93.9
42
Hard-hit allowed47.0%
9
Whiff%21.8%
41 -29 vs proj
Mithrandir+

Stuff+ and arsenal context

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

2026-06-12
Changeup Stuff+93
7
Fastball Stuff+102
49
Mithrandir Stuff+105
72
Sinker Stuff+101
37
Slider Stuff+113
98
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 Romero, JoJo · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.313 0.341 2026-06-01: 0.3312026-06-02: 0.3312026-06-03: 0.3312026-06-04: 0.3352026-06-05: 0.3392026-06-06: 0.3392026-06-07: 0.3392026-06-08: 0.3392026-06-09: 0.3392026-06-10: 0.3392026-06-11: 0.3392026-06-12: 0.341 2026-06-01 2026-06-12 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 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 Romero, JoJo · Aggregate zone metrics; not pitch-by-pitch locations Edge: 37%37%Zone: 45%45%Whiff: 22%22%Called strike: 22%22%First pitch strike: 48%48%Hard hit allowed: 47%47% 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 Romero, JoJo · 2026 arsenal snapshot Sinker: 43.5%Sweeper: 36.6%Changeup: 17.7%4-Seam Fastball: 2.1% SI44% · 94 mphprimary pitch SI 44%ST 37%CH 18%FF 2% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Romero, JoJo · 2026 arsenal snapshot 12″24″36″48″ Sinker: 44% usage, 4″ horizontal break, 30″ drop, 93.9 mphSI94 mphSweeper: 37% usage, 2″ horizontal break, 40″ drop, 82.9 mphST83 mphChangeup: 18% usage, 12″ horizontal break, 37″ drop, 87.2 mphCH87 mph4-Seam Fastball: 2% usage, 3″ horizontal break, 18″ drop, 94.3 mphFF94 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
SI 42.5% 186 101 limited sample
SL 37.0% 162 113 limited sample
CH 18.3% 80 93 limited sample
FB 2.3% 10 102 limited sample
Method note

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

Reference layer

Current snapshot

Age29
Height5' 11"
Weight215 lb
Debut2020-08-21
Live layer

Delta / regression

ERA Δ-0.07
K% Δ+0.028

negative regression

Regression watch

Running hot. Expect some cooling.

-0.4σ gap
wOBA-against (actual)0.327
xwOBA-against (deserved)0.341

Romero’s wOBA-against sits at 0.327, but the quality of contact underneath says it should be 0.341 — a gap of 0.014, -0.4 standard deviations from the MLB norm over 31 IP. The results have outrun the underlying process; as the sample grows, expect the numbers to drift back toward the deserved level.

Mithrandir coverage

Module shelf

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

Available detail

Pitcher Projections 202622.4% K | 3.61 ERAProjection
2026-04-17 @ HOU0 ER / 0 K1.0 IP
2026-04-15 vs CLE0 ER / 1 K1.1 IP
2026-04-14 vs CLE0 ER / 0 K1.1 IP
2026-04-06 @ WSH0 ER / 0 K1.0 IP
2026-04-05 @ DET0 ER / 1 K1.2 IP