Mithrandir Metrics
Pitcher projection 2026 Refreshed Sep 27 06:00 AM ET
Pitcher projection / PIT · 2026

Mattson, Isaac

Run-prevention profile built on workable command

Primary
22.2% K%
Range
16.8% to 29.2%
Live Δ
yes
Team PIT Archetype Balanced reliever Age 31 Status IL-15
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.

2026-09-27
21
Pitching
percentile
Pitching9 metrics
19
Arsenal5 metrics
41
Rolling projection

Preseason / current pace / Bayesian update

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

2026-09-27
ERA preseason4.33
ERA current pace5.35
ERA rolling p504.77
Observed weight43%
ERA
3.35 4.03 4.77 5.52 6.20
FIP
2.58 3.27 4.04 4.82 5.51
K%
18.3% 20.2% 22.2% 24.2% 26.1%
BB%
7.5% 8.7% 10.1% 11.5% 12.7%
Current percentile strip

Actual percentile with projection tick

100th = best in MLB.

2026-09-27
Pitching · percentile strip
WHIP1.61
11
ERA5.35
20
BB%10.3%
33
K%20.7%
39
xwOBA allowed0.374
5 -41 vs proj
Barrel allowed11.9%
4 -43 vs proj
Fastball velo94.2
46
Hard-hit allowed52.4%
0
Whiff%18.3%
15 -29 vs proj
Mithrandir+

Stuff+ and arsenal context

Stuff+ appears when the current pitch-event scoring artifact includes this pitcher; Arsenal Decomposition remains descriptive support under Stuff+.

2026-09-27
Fastball Stuff+102
51
Changeup Stuff+96
15
Curveball Stuff+106
97
Mithrandir Stuff+101
40
Slider Stuff+92
4
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 71%Top usage
ride armside gloveside +Arsenal gap +Shape contrast
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 Mattson, Isaac · Live snapshot series; true 50/100 PA windows require PA-level logs LG AVG 0.313 0.374 2026-09-13: 0.3742026-09-14: 0.3742026-09-18: 0.3742026-09-19: 0.3742026-09-20: 0.3742026-09-21: 0.3742026-09-22: 0.3742026-09-23: 0.3742026-09-24: 0.3742026-09-25: 0.3742026-09-26: 0.3742026-09-27: 0.374 2026-09-13 2026-09-27 xwOBA allowed MITHRANDIR · CHARTS
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 Mattson, Isaac · Aggregate zone metrics; not pitch-by-pitch locations Edge: 33%33%Zone: 51%51%Whiff: 18%18%Called strike: 15%15%First pitch strike: 47%47%Hard hit allowed: 52%52% 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.

2026
Mithrandir Metrics PITCH ARSENAL DONUT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Mattson, Isaac · 2026 arsenal snapshot 4-Seam Fastball: 70.8%Slider: 12.2%Changeup: 10.1%Sweeper: 6.9% FF71% · 94 mphprimary pitch FF 71%SL 12%CH 10%ST 7% MITHRANDIR · CHARTS
Mithrandir Metrics PITCH MOVEMENT Parameterized Mithrandir chart rendered as SVG for templates and exports. Pitch Arsenal Mattson, Isaac · 2026 arsenal snapshot 12″24″36″48″ 4-Seam Fastball: 71% usage, 1″ horizontal break, 13″ drop, 94.2 mphFF94 mphSlider: 12% usage, 1″ horizontal break, 36″ drop, 84.5 mphSL84 mphChangeup: 10% usage, 8″ horizontal break, 31″ drop, 86.0 mphCH86 mphSweeper: 7% usage, 3″ horizontal break, 41″ drop, 83.0 mphST83 mph less drop ↑ more drop ↓ · horizontal break ↔ · dot size = usage · break incl. gravity MITHRANDIR · CHARTS
PitchUsagePitchesStuff+Status
FB 77.1% 353 102 qualified
CH 10.3% 47 96 limited sample
SL 8.1% 37 92 limited sample
CB 4.6% 21 106 limited sample
Method note

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

Model read

Projection notes

1
templated note
Needs the arsenal to hold up against lefties (0.274 vs 0.247 xwOBA allowed split).
pitcher
2
templated note
Volume stays relief-shaped even when the bat-miss traits are strong.
pitcher
3
templated note
Home park gives the run-prevention profile a small HR cushion.
pitcher
4
templated note
Primary mix entering the season: 4-Seam Fastball 78%, Changeup 12%, Slider 9%.
pitcher
Live context

Current-season signal

ERA Δ+0.97
K% Δ-0.015
Sample39.7 IP

negative regression

Projection table

Point projection and range

MetricPointRangeHalf-width
Innings33.4----
Batters Faced138----
K%22.2%16.8% to 29.2%+/- 6.2%
BB%10.1%6.8% to 14.8%+/- 4.0%
Whiff%21.8%16.6% to 26.8%+/- 5.1%
HR/91.190.32 to 1.79+/- 0.74
xwOBA Against0.3170.264 to 0.348+/- 0.042
Barrel% Allowed7.6%3.5% to 11.3%+/- 3.9%
ERA4.381.67 to 5.65+/- 1.99
FIP4.102.98 to 7.09+/- 2.05
WHIP1.3870.927 to 1.609+/- 0.341
Platoon / Shape
vs LHH

123 career BF

xwOBA0.274
K%19.6%
BB%11.2%
Barrel6.9%
vs RHH

148 career BF

xwOBA0.247
K%20.8%
BB%7.5%
Barrel6.1%