Mithrandir Metrics
Player St. Louis Cardinals Refreshed Sep 1 06:00 AM ET
Player profile / St. Louis Cardinals

Riley O'Brien

P · Bats/Throws R/R · 6' 4", 180 lb · Age 31

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

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
20240011.258008.0112.63
2025312.06420648.0451.15
2026363.955603454.2541.23
5 Seasons683.74108140113.01131.33
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
50
Pitching
percentile
Pitching9 metrics
55
Arsenal3 metrics
61
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
Pitching · percentile strip
WHIP1.26
63
ERA3.93
53
BB%9.4%
44
K%23.8%
61
xwOBA allowed0.334
28
Barrel allowed6.7%
62
Fastball velo97.9
93
Hard-hit allowed42.7%
21
Whiff%24.9%
66
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
Mithrandir Stuff+105
79
Sinker Stuff+107
87
Slider Stuff+97
17
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 O'Brien, Riley · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.313 0.334 2026-08-21: 0.3182026-08-22: 0.3182026-08-23: 0.3182026-08-24: 0.3182026-08-25: 0.3342026-08-26: 0.3342026-08-27: 0.3352026-08-28: 0.3332026-08-29: 0.3332026-08-30: 0.3332026-08-31: 0.3332026-09-01: 0.334 2026-08-21 2026-09-01 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 59%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 O'Brien, Riley · Aggregate zone metrics; not pitch-by-pitch locations Edge: 36%36%Zone: 45%45%Whiff: 25%25%Called strike: 18%18%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 O'Brien, Riley · 2026 arsenal snapshot Sinker: 59.3%Sweeper: 31.3%Slider: 8.4%Changeup: 0.9% SI59% · 98 mphprimary pitch SI 59%ST 31%SL 8%CH 1% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal O'Brien, Riley · 2026 arsenal snapshot 12″24″36″48″ Sinker: 59% usage, 1″ horizontal break, 24″ drop, 97.9 mphSI98 mphSweeper: 31% usage, 1″ horizontal break, 44″ drop, 83.1 mphST83 mphSlider: 8% usage, 2″ horizontal break, 29″ drop, 90.8 mphSL91 mphChangeup: 1% usage, 6″ horizontal break, 29″ drop, 90.8 mphCH91 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
SI 57.9% 334 107 qualified
SL 41.4% 239 97 qualified
CH 0.7% 4 88 limited sample
Method note

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

Reference layer

Current snapshot

Age31
Height6' 4"
Weight180 lb
Debut2021-09-28
Live layer

Delta / regression

ERA Δ--
K% Δ--

negative regression

Regression watch

Running hot. Expect some cooling.

-0.5σ gap
wOBA-against (actual)0.319
xwOBA-against (deserved)0.334

O'Brien’s wOBA-against sits at 0.319, but the quality of contact underneath says it should be 0.334 — a gap of 0.015, -0.5 standard deviations from the MLB norm over 56 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 202623.0% K | 4.01 ERAProjection
2026-08-15 @ CHC0 ER / 0 K1.0 IP
2026-04-15 vs CLE0 ER / 2 K1.0 IP
2026-04-14 vs CLE0 ER / 1 K1.0 IP
2026-04-08 @ WSH0 ER / 0 K1.0 IP
2026-04-07 @ WSH0 ER / 2 K1.0 IP