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Robot umpires flip 54% of challenged calls in ABS debut as teams learn to time appeals

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Cite

Blum, R. (2026, October 2). Robot umpires flip 54% of challenged calls in ABS debut as teams learn to time appeals. Toronto Star. https://www.thestar.com/sports/robot-umpires-flip-54-of-challenged-calls-in-abs-debut-as-teams-learn-to-time-appeals/article_5a691c7c-9d97-5215-adde-c2e085e8f579.html

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Toronto Star · collected 2026-10-02 · by Ronald Blum

Quick Summary

In the first season of MLB’s Automated Ball-Strike System (ABS), robot umpires overturned 54% of challenged calls. Catchers were more successful than batters, with a 59% success rate compared to 49%. The Cincinnati Reds had the highest net gain in runs from challenges at 16.8, while several playoff teams performed poorly by this metric. Houston’s Jose Altuve and Seattle’s Cal Raleigh led in runs gained through batter challenges, while Cubs’ Seiya Suzuki topped in runs lost defensively.
Written by AI on 2026-10-02, from this article's own text only (the story summary below draws on all the coverage).

AI analysis

Story summary

In the debut season of MLB's Automated Ball-Strike System, robot umpires overturned 54% of challenged calls, significantly impacting game outcomes. Catchers were more successful than batters in challenging pitches, with teams like the Cincinnati Reds gaining a net 16.8 runs from overturns compared to playoff contenders such as the Los Angeles Dodgers losing -8.5 runs. Players learned to strategically time their challenges; for instance, Houston’s Jose Altuve maximized his gains at 5.6 projected runs, while the Cubs’ Seiya Suzuki faced a loss of 5.7 runs in defensive calls. Teams are adapting by refining their strategies on when to challenge and when not to, as highlighted by Padres manager Craig Stammen's remarks about ongoing adjustments throughout the season.

Written for “Robot Umpires Debut” on 2026-11-04, grounded in this article and the 0 other(s) covering the same event.

Story

📰 Robot Umpires Debut
Technology · 1 article(s) covering the same event.

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Claims extracted
50
sentences that state something as happening or true
Uncertain
4%
2 of 50 hedged ("reportedly", "may", "according to")
Leaning
not political
takes no side on a contested political question
Publisher signals
64/100
Toronto Star's corrections and hedging, across everything collected from it. Not a measure of accuracy.
Outlets on this story
1
Technology
Same framing elsewhere
1
articles that frame the event the way this one does
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Publisher

Toronto Star · 11416 article(s) · 28 correction(s) detected
Running correction rate · 28 correction(s)
2026-10-26
Correction
2026-10-24
Correction
2026-10-07
Correction
2026-09-24
Correction

Who wrote this

Ronald Blum
29 article(s) here · 1 carrying a prediction
🔮 Players could start negotiating terms with all teams at 5 p.m. Eastern Monday.
🔮 Starting pitchers Sonny Gray and Nick Martinez also will become free agents after their teams declined mutual options.
🔮 When Jake Bauers gloved the final out of the Milwaukee Brewers’ first World Series triumph, it might have ended the last Major League Baseball game for a long time.
🔮 A month shy of his 68th birthday, Murphy could soon become the first person to win a Manager of the Year award in three straight seasons.
🔮 ST. PETERSBURG, Fla. (AP) — Jacob Misiorowski pitched with poise when he couldn’t overwhelm with punishing heat, overcoming Tampa Bay batters and the Tropicana Field mound to lead the Milwaukee Brewers to their first World Series title.
🔮 William Contreras became the eighth catcher voted the World Series MVP after lifting the Milwaukee Brewers to their first World Series championship.
🔮 A month shy of his 68th birthday, Murphy could soon become the first person to win a Manager of the Year award in three straight seasons.
🔮 Tampa Bay, which won the AL pennant by forcing opponents into mistakes, committed one error, made two other misplays that could have been charged as errors, and had a runner thrown out at the plate.
🔮 MILWAUKEE (AP) — A few inches here and some smarter baserunning by Victor Mesa Jr. there, and the Tampa Bay Rays might have won the World Series opener.
🔮 Baseball’s labour contract expires Dec. 1, and management is expected to immediately lock out the players.
Also by Ronald Blum
Nothing else under this byline is closely related to this article, so these are simply their most recent.
All 29 articles by Ronald Blum →

Topics

Atlanta Cleveland Cubs Houston Milwaukee

Subjects

Cubs ORG · 4× Cincinnati GPE · 3× Cleveland GPE · 3× Colorado GPE · 3× Houston GPE · 3× Philadelphia GPE · 3× Athletics ORG · 2× Atlanta GPE · 2× Milwaukee GPE · 2× Minnesota GPE · 2×

Narrative

Pittsburgh was least successful at 47%, with the White Sox and Cleveland at 49% each, and Baltimore and San Diego at 50%. “We’ll keep tweaking it, keep talking about it every day and keep trying to remind the players when we have challenges, when we don’t, when’s a good time, when’s not a good time,” Padres manager Craig Stammen said.
framing: assertive · carried by 1 article(s) · first seen 2026-10-02
🔮 Houston’s Jose Altuve topped batters with 5.6 projected runs gained, followed by Seattle’s Cal Raleigh (4.6), Colorado’s Kyle Karros (4.5) and Cincinnati’s Sal Stewart (4.4) and JJ Bleday (4.1).

Claims (50 extracted, 2 hedged)

NEW YORK (AP) — Robot umpires overturned 54% of challenged calls in the first season of the Automated Ball-Strike System, and catchers were far more successful than batters. asserted
catchers → overturn → batters
Learning when to challenge is key. asserted
Learning → learn → ?
The Cincinnati Reds had a net gain of 16.8 runs, according to Baseball Savant calculations of total run value of overturns on challenges. uncertain
Reds → have → challenges
The Los Angeles Angels were next at 14, followed by the Athletics (12.3) and Minnesota (10.1). asserted
Angels → follow → Athletics
Cleveland was 30th at minus-13.4 and several other playoff teams rated poorly by that metric: the Los Angeles Dodgers (26th, -8.5), Tampa Bay (25th, -7.8), the Chicago Cubs (21st, -4.6), Milwaukee (20th, -2.4), Atlanta (18th, -2.1), San Diego (17th, -1.9), the New York Yankees (16th, -2.1) and Houston (15th, -0.8). asserted
teams → rat → metric
Houston’s Jose Altuve topped batters with 5.6 projected runs gained, followed by Seattle’s Cal Raleigh (4.6), Colorado’s Kyle Karros (4.5) and Cincinnati’s Sal Stewart (4.4) and JJ Bleday (4.1). asserted
Altuve → top → Raleigh
The Cubs’ Seiya Suzuki led with 5.7 runs projected lost in defensive challenges, just ahead of the Dodgers’ Shohei Ohtani (5.5), the Cubs’ Ian Happ (5.2) and Michael Busch (5.1), and the New York Mets’ Brett Baty (3.5). asserted
Suzuki → lead → Ohtani
Milwaukee’s William Contreras led catchers with 5.2 projected runs prevented, just in front of Cleveland’s Patrick Bailey (5.1), the Mets’ Francisco Alvarez (4.5) and San Diego’s Freddy Fermin, Kansas City’s Carter Jensen and Drew Romo of the Chicago White Sox (all 4.3). asserted
all → lead → Sox
“It’s like a new muscle for players to learn,” Yankees manager Aaron Boone said. asserted
Boone → ’ → muscle
“You have instincts over what to do in certain situations. asserted
You → have → situations
This is a new instinct of knowing when to challenge and instinctively within a second, oh, that’s a ball. asserted
that → know → second
What’s the situation?” asserted
situation → ’ → ?
There were 10,557 challenges, an average of 4.35 per game, and 5,686 led to overturned decisions. asserted
5,686 → be → decisions
Catchers succeeded on 59% of their challenges, while batters had a 49% success rate and pitchers — who seldom challenged compared to catchers and batters — were at 40%. asserted
who → succeed → %
“ABS has really impacted the game,” Houston manager Joe Espada said. asserted
Espada → impact → game
“It has really changed how more selective some of these lineups are, how more disciplined they are, how we force pitchers to be more aggressive in the zone more than in the past.” asserted
we → change → past
Contreras, Realmuto stand out among players Contreras led all catchers with 185 challenges, and he also won the most with 105 (57%). asserted
he → stand → 105
Meanwhile, Philadelphia’s J.T. Realmuto had the highest success rate among catchers with at least 75 challenges at 81%. asserted
Realmuto → have → %
He was followed by the Cubs’ Carson Kelly (69%), Cincinnati’s Tyler Stephenson and Colorado’s Hunter Goodman (68% each), and Detroit’s Dillon Dingler (66%). asserted
He → follow → Kelly
Realmuto added the first game-ending ABS challenge in postseason history this week, successfully flipping a call to end Game 2 of the Phillies’ NL Wild Card Series against Atlanta. asserted
Realmuto → add → Atlanta
Stewart led batter challenges with 51 appeals and won 28 (55%). asserted
Stewart → lead → 28
Philadelphia’s Bryce Harper was next with 47, winning 21 (45%). asserted
Harper → win → 21
On success rate, Arizona’s Gabriel Moreno (68%) led batters with 20 or more challenges, followed by Miami’s Esteury Ruiz (65%), Raleigh (64%), Minnesota’s Josh Bell and San Francisco’s Bryce Eldridge (62% each). asserted
Moreno → lead → Ruiz
Tampa Bay’s Yandy Díaz had 686 plate appearances without attempting a challenge, by far the most in the majors by a batter, ahead of Toronto’s Nathan Lukes (450). asserted
Díaz → have → Lukes
Díaz has said he’d consider challenging a call in the World Series. asserted
he → say → Series
Cincinnati’s 62% success rate led MLB, followed by the Athletics and Arizona (60% each), the Cubs (59%), Texas (58%), Detroit and Philadelphia (57% each) and Miami (56%). asserted
rate → lead → Athletics
Pittsburgh was least successful at 47%, with the White Sox and Cleveland at 49% each, and Baltimore and San Diego at 50%. “We’ll keep tweaking it, keep talking about it every day and keep trying to remind the players when we have challenges, when we don’t, when’s a good time, when’s not a good time,” Padres manager Craig Stammen said. asserted
Stammen → keep → challenges
Players were more aggressive with ABS challenges in late innings Knowing teams lose their right to challenge after two incorrect appeals, players used ABS less often early in games. asserted
players → know → games
There were more challenges in the ninth than any other inning — sometimes because teams knew there would be no later innings to save them for — even though many games end without the bottom half. asserted
games → be → half
ABS was used in 1,366 ninth-inning challenges, with a 40% success rate. asserted
ABS → use → rate
“Having one in your pocket is kind of — it’s nice to know you have it,” Phillies interim manager Don Mattingly said. asserted
Mattingly → have → it
Teams also got more aggressive as the season went on. asserted
season → get → ?
Challenges per game rose from 3.76 in March to 4.60 in August and 4.61 in September, with most of that increase in catcher appeals. asserted
Challenges → rise → appeals
“You can overthink it if you let yourself,” Atlanta manager Walt Weiss said. asserted
Weiss → overthink → yourself
“You start talking about saving it for certain situations, it probably doesn’t end well. asserted
it → start → situations
My message was the lower the leverage, the more certainty you have to have.” asserted
you → have → certainty
Overturn rate for umpires most often behind plate ranged from 42-66% Andy Fletcher had the highest overturn rate among umpires with more than 100 challenges, getting reversed on 80 of 121 (66.1%), according to taptochallenge.com. uncertain
Fletcher → range → taptochallenge.com
Rob Drake was next at 64.6%, followed by Cory Blaser (64.1%), Adrian Johnson (64%), Manny Gonzalez (62.5%) and Mike Estabrook (61.7%). asserted
Drake → follow → Blaser
Jansen Visconti had the lowest overturn rate among those with triple-figure challenges, reversed on 43 of 102 (42.2%). asserted
Visconti → have → 102
“When it gets overturned by less than a 10th of an inch, they do not like it,” Realmuto said of umpires. asserted
Realmuto → overturn → umpires
…and 10 more, not listed.
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