MLB ABS Umpire Tracker

Every Automated Ball-Strike challenge in the 2026 MLB regular season, joined to the home-plate umpire who made the original call. Refreshed daily after the last game.

ABS Challenges
392
events captured
Overturned
210
calls flipped by ABS
League Overturn Rate
53.6 %
of all challenges
Plate Umpires
65
tracked this season
Last Game
2026-05-16
most recent ingest

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🚨
10 umpires have been overturned at ≥55% over five or more challenges this season. These are the plate umpires the ABS system is correcting most often.
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The catcher knows best

58.2 %

Catchers win 58.2% of the challenges they call. Pitchers? Just 27.3%. Don't waste your challenges on what the guy on the mound thinks.

ABS is pitcher-friendly

+ 13

Net strikeouts added by overturned challenges. ABS has handed pitchers 13 more K's than it's taken away — and removed 2 walks on balance.

First-pitch ambush

63.4 %

The 0-0 count is challenged most often AND overturned at 63.4%. Hitters and catchers are leading off at-bats with high-confidence challenges.

Sharpest challengers

CWS

The CWS lead the league with a 75% challenge-success rate (minimum 8 attempts). Their bench knows when to pull the trigger.

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The shadow zone — where ABS overturns most

Every pixel below is a region of the strike zone, viewed from the catcher's perspective. Darker red = umpires are getting overturned more often when they call pitches in that location. The number inside is the overturn rate; the cell size reflects challenge volume.

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Reading the grid. The four corners of the zone are battleground real estate. The outside corner, below zone band lights up brightest — pitches the umpire called as strikes that the ABS zone says clearly weren't. The inside corner, high region is the second-worst miss. Heart-of-plate calls are rarely overturned because they're rarely close.


League distribution

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Full leaderboard

🚨 = ≥65% overturned (8+ challenges) ⚠️ = ≥60% overturned (5+ challenges) Reliable % = Wilson 95% lower bound — corrects for small samples RV swing = absolute run-value change from overturned calls
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Why two percentages? Raw % treats a 1-of-1 the same as a 25-of-50 — both show 100% / 50%. The Reliable % column applies the Wilson 95% confidence lower bound, which shrinks small-sample numbers toward the league mean. Sort by Reliable % to see which umpires the ABS system is correcting consistently, not just occasionally with luck.


The fair view — accuracy on every called pitch

Challenge data only covers ~5% of pitches and is biased toward calls players think are wrong. The view below is built from every called pitch in 2026 (104,000+), classified against the ABS strike zone independently. This is the unbiased accuracy metric.

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What "stolen strikes" means. A called strike on a pitch that the ABS zone says was a ball — the umpire gave the pitcher a strike that wasn't there. Lost strikes = the inverse (ball called on a pitch in the zone). The Net bias column is positive when the umpire systematically favors pitchers (stolen − lost). Across MLB, stolen strikes outnumber lost strikes ~20-to-1 — umpires are pitcher-friendly, and ABS now measures by how much.


Biggest moments of the season

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Latest overturned calls

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Every challenge

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