99% Invisible – "RoboUmp Hits the Big Leagues" (April 14, 2026)

Host: Roman Mars
Producer/Co-Host: Chris Berube
Guests: Katie Nolan (Baseball Analyst), Zach Helfand (New Yorker Sports Writer), Fred DeJesus (Umpire)

Episode Overview

This episode explores Major League Baseball’s historic adoption of robot umpires—officially the Automated Balls and Strikes (ABS) system—and the wider implications of introducing technology into a tradition-heavy sport. The episode revisits a previous 99% Invisible segment on ABS in the minor leagues before updating listeners on how the system is faring in the majors in 2026.
Through expert interviews, personal anecdotes, and recent events, the show examines the design, challenges, and human element of umpiring—and what’s gained and lost when robots replace people on the field.

Key Discussion Points and Insights

1. Why Robot Umpires? The Problem of Human Error

• Baseball’s Flawed Calls:
  • Historic example (Levan Hernandez, 1997 NLCS): Recounting a game where umpire Eric Gregg called numerous erroneous strikes, ultimately affecting the outcome and raising questions about umpiring accuracy.
    • Katie Nolan (03:20): "This pitch is, I would say, a foot, two feet outside of the strike zone. Not close, called a strike."
    • Narrator (04:00): “It was probably the worst umpiring I can remember. The outside of this strike zone, it just didn’t end.”
  • Statistics on Mistakes:
    • Roman Mars (05:56): "One study from 2018 found that umpires blow about 14 calls every game. That's 34,000 bad calls every year. And it makes a difference."

2. The Technology: Evolution from Novelty to Reality

• Early Prototypes:
  • The 1950s saw unsuccessful robot ump attempts (clunky, inaccurate, failed under certain conditions).
  • Modern systems draw from missile-tracking tech, now refined and accurate.
• What ABS Really Is:
  • Not a physical robot, but a network of high-def cameras and tracking software that instantly determines balls and strikes.
    • Zach Helfand (08:00): “What it really is, it’s this system… Actually a series of HD cameras.”
  • Already used in other sports (e.g., Hawk-Eye in tennis).

3. Design Challenges: “Textbook” vs. “Human” Strike Zones

• RoboUmp’s Early Shortcomings:
  • Initial programming adhered strictly to the rulebook, causing confusion as human umpires slightly expand the zone for hittable pitches.
    • Roman Mars (15:27): “The robot was calling a lot of hittable pitches as balls.”
  • The system was reprogrammed to better match human expectations, expanding the zone slightly to "better represent the real strike zone" (Zach Helfand, 16:03).

4. Human Element: The Unwritten Art of Umpiring

• Contextual adjustments:
  • Human umpires subtly change their calls based on weather, score, or compassion—a quality robots lack.
    • Zach Helfand (16:32): “It’s raining. Let’s move this along. Or one team is up by a lot. Let’s just go home...That’s what they call the compassionate umpire effect.”
• Baseball’s Romance with Imperfection:
  • Debate over whether absolute accuracy is desirable or if charm and unpredictability are integral to the game.
    • Narrator (16:54): “You’re taking away one of those small imperfections that makes baseball kind of romantic.”

5. Experience in the Minor Leagues: Introducing ABS

• Hybrid Human-Robot Collaboration:
  • Humans still announce the calls, using robot data via earpieces.
    • Zach Helfand (11:46): “The ball hits the glove, and a split second later you hear ‘strike’ or ‘ball.’”
    • Fred DeJesus (12:30): “I obviously couldn’t get there as a player, so I made my earpiece made. My joke is six Puerto Ricans have made it and one Puerto Rican's earpiece has made it."
  • The robot ump boosts accuracy, but minor glitches and adjustment periods exist.
    • Fred DeJesus (13:26): “It was pretty damn good. Very accurate. There were times where you would go, ooh, but again, you did what that machine wanted.”

6. Psychological and Social Effects

• Reducing Conflict and Abuse:
  • Fans and players argue less with robots, as there’s less ambiguity (and less point in heckling a machine).
    • Zach Helfand (19:41): “Fans were a lot less likely to get into arguments when they knew it was a machine making the calls.”
    • Narrator (20:36): Describes seeing a player stop himself from arguing a call, knowing it was the robot’s determination.
• Human Costs Remain:
  • Umpiring is still a tough, often thankless job, involving not just fans’ ire but sometimes violence.
    • Katie Nolan (18:07): "Imagine going to work knowing you could get a shard of wood directly into your face...The like ceiling of this job is...You make calls that get people to tell you that you suck at your job..."
    • Fred DeJesus (18:29): “I’ve got a video… where the player is saying, ‘Freddy, you’re the worst umpire in the league.’ Now he’s obviously joking, but this is what the world wants to hear. They want umpires to be ridiculed.”

Major League Update (2026): How ABS Works Now

[24:11] – Onward to the Majors: The Challenge System

New Implementation:

• The ABS is now part of MLB as a challenge system—human umpires still call pitches, but players can appeal to the robot for a second opinion.
  • Chris Perube (24:18): “…the robot umpire has arrived in Major League Baseball, but not in the way that I was predicting…now, human umpires are still making every ball and strike call. But if a player disagrees, they can challenge the call.”
  • Roman Mars (25:04): Live narration of an ABS challenge, seeing the process play out.

How It Works:

• Teams get two ABS challenges per game; a successful challenge restores the right, so teams must be selective.
  • Chris Perube (26:29): “Each team only gets two challenges a game…but if you make a successful challenge, you get to keep it.”

Fan & Player Response:

• Players appreciate a formal avenue for recourse after questionable calls.
  • Chris Perube (27:13): “…before, if there was a bad call, they had to kind of grin and bear it…But now a few times a game, they can get a call overturned…”
• Fans are finding the new layers of drama “surprisingly fun,” as challenges are communal, real-time events.
  • Chris Perube (27:49): “It's actually creating more drama…everybody looks up at the scoreboard together…and then fans go crazy when their team is right in their challenges.”

Notable Quotes & Moments

• Roman Mars (25:04 – 25:37): [Narrating a challenge as seen on video] “…the catcher taps his helmet. Okay. And then the umpire goes to the side to check what's happening. All right…then they show a graphic of the ball just sort of hitting the bottom of the strike zone.”
• Chris Perube (25:40): “That's a really close borderline call. So the fact the catcher knew to challenge that one is impressive.”

[28:36] – The Human Cost: Spotlight on Umpires

• High-PPublic Humiliation:

  • The new system can subject umpires to embarrassing scrutiny, fueling social media pile-ons.
    • Chris Perube (28:36): “For the accurate umpires, like, doesn't really matter that much. But for the ones who make mistakes more often…there's a couple of umpires who have been genuinely humiliated…”

• "CB Buckner Incident":

  • Umpire CB Buckner becomes infamous after 6 challenged, overturned calls in a single week—inviting viral criticism and highlighting ABS’s potential to put umpires under a public microscope.
    • Chris Perube (29:34–32:11): Detailed play-by-play of Buckner’s rough week, noting race and job tenure factors in his scrutiny.

• Roman Mars (32:12): “Absolutely. He's just having the worst week ever. My sympathies, for sure.”

• Chris Perube (32:17): “...It has kind of done the opposite of what I was thinking the robot umpires would accomplish.”

Timestamps for Important Segments

• [00:55] – Introduction to RoboUmp in MLB
• [02:24] – Revisiting the infamous 1997 NLCS umpiring
• [05:56] – Human umpires' error rates and impact
• [07:04] – History of robotic umpire attempts
• [08:00] – How ABS technology works
• [10:15] – Minor League experiments with ABS
• [12:18] – Human-robot hybrid: Fred DeJesus’s experience
• [15:27] – Programming the "real" strike zone
• [19:41] – ABS reduces fan/umpire conflict
• [24:11] – 2026 update: MLB adopts challenge-based ABS
• [28:36] – The human impact: Umpires’ new public challenges
• [29:34] – The CB Buckner controversy
• [33:01] – Wrapping up: Wait and see for the rest of the season

Memorable Moments & Quotes

• On Human Error:
  • Katie Nolan (03:27): “Egregious. Egregious.”
• On Changing the Strike Zone:
  • Zach Helfand (16:32): “That’s what they call the compassionate umpire effect.”
• On Fan Culture:
  • Narrator (17:34): “Yelling at the umpire is a part of the game.”
• On New Drama:
  • Chris Perube (27:49): “Instead, it is this moment of player versus umpire with the robot as the arbitrator. And that's actually kind of fun."
• On Unintended Consequences:
  • Chris Perube (32:17): “It has put this person under a microscope. It has empowered people to yell at this guy and be mean to him on social media and stuff.”

The 99% Invisible Takeaway

"RoboUmp Hits the Big Leagues" thoughtfully balances the promise and pitfalls of automation in America's most tradition-bound game. The ABS system corrects human errors and adds new drama—but not without fresh challenges, especially for human umpires now more exposed than ever. As the 2026 season unfolds, baseball continues its uneasy negotiation between nostalgic imperfection and technological precision.

Further Reading:

• Zach Helfand’s New Yorker article on robot umpires
• Katie Nolan’s new podcast, “Casuals”