Mithrandir Metrics
Player St. Louis Cardinals Refreshed Jul 18 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 Active Status Healthy / active roster
Traditional line

Season by season

3D Pitch Lab Projections
WLERAGGSSVIPSOWHIP
20240011.258008.0112.63
2025312.06420648.0451.15
2026333.354002540.1401.14
5 Seasons653.479213198.2991.31
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.

2026-07-18
63
Pitching
percentile
Pitching9 metrics
66
Arsenal3 metrics
59
Rolling projection

Preseason / current pace / Bayesian update

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

2026-07-18
ERA preseason3.78
ERA current pace3.43
ERA rolling p503.63
Observed weight42%
ERA
1.91 2.72 3.63 4.54 5.36
FIP
2.47 2.90 3.38 3.86 4.29
K%
19.3% 21.2% 23.4% 25.6% 27.6%
BB%
5.8% 7.2% 8.8% 10.4% 11.8%
Live percentile strip

Current traits vs projection tick

100th = best in MLB.

2026-07-18
Pitching · percentile strip
WHIP1.16
74
ERA3.43
66
BB%7.5%
68 +36 vs proj
K%24.7%
66
xwOBA allowed0.323
40
Barrel allowed6.5%
70
Fastball velo98.2
94
Hard-hit allowed40.7%
38
Whiff%26.8%
77 +21 vs proj
Mithrandir+

Stuff+ and arsenal context

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

2026-07-18
Sinker Stuff+107
87
Mithrandir Stuff+105
75
Slider Stuff+96
15
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 0.314 0.323 2026-07-07: 0.3252026-07-08: 0.3252026-07-09: 0.3252026-07-10: 0.3242026-07-11: 0.3242026-07-12: 0.3222026-07-13: 0.3232026-07-14: 0.3232026-07-15: 0.3232026-07-16: 0.3232026-07-17: 0.3232026-07-18: 0.323 2026-07-07 2026-07-18 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: 44%44%Whiff: 27%27%Called strike: 17%17%First pitch strike: 48%48%Hard hit allowed: 41%41% 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: 58.7%Sweeper: 29.8%Slider: 10.4%Changeup: 1.1% SI59% · 98 mphprimary pitch SI 59%ST 30%SL 10%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, 0″ horizontal break, 24″ drop, 98.2 mphSI98 mphSweeper: 30% usage, 1″ horizontal break, 43″ drop, 83.6 mphST84 mphSlider: 10% usage, 2″ horizontal break, 28″ drop, 91.1 mphSL91 mphChangeup: 1% usage, 3″ horizontal break, 28″ drop, 90.9 mphCH91 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
SI 57.9% 243 107 qualified
SL 41.7% 175 96 limited sample
CH 0.5% 2 75 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-0.54
K% Δ+0.017

negative regression

Regression watch

Running hot. Expect some cooling.

-0.4σ gap
wOBA-against (actual)0.311
xwOBA-against (deserved)0.323

O'Brien’s wOBA-against sits at 0.311, but the quality of contact underneath says it should be 0.323 — a gap of 0.012, -0.4 standard deviations from the MLB norm over 41 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 | 3.97 ERAProjection
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
2026-04-05 @ DET0 ER / 1 K1.0 IP