The ABS challenge system has been one of the best stories in baseball so far this season, and Jeff Passan has been one of the best people to follow on the subject.

The ESPN MLB insider has been ahead of this story for a couple of years now, going back to his appearances on The Rich Eisen Show in 2024 when he was making the case that automated ball-strike technology was the only real fix for a broken umpire accountability system. Now that ABS is actually here and working, Passan is still the best voice on how the system actually functions. And while discussing it with Eisen this week, he revealed a detail most people don’t know.

Umpires have a two-way microphone that connects them to the ABS operator during games. If a home plate umpire’s zone drifts, someone can tell him in real time — mid-game, mid-inning — to bring it back in.

“MLB, I think, has done a decent job of giving umpires the ability to get in-game feedback,” Passan said. “I don’t know if you knew this, but umpires have a two-way microphone and they can talk to the ABS operator and can be told that ‘Hey, you’re calling strikes a little bit off the plate today. Bring it in a little bit.’ And that real-time feedback, I think, has helped.”

For most of baseball’s recent history, umpires were graded on a curve wide enough to make almost everyone look competent and protected by the union from any meaningful public accountability. When Ángel Hernández finally retired in 2024, Passan was on the same show arguing that public pressure from fans and the media had done what the league’s own system never could.

Apparently, ABS has been doing the same thing quietly, pitch by pitch, without anyone knowing about it until this week.

Passan re-signed with ESPN in March on a multi-year deal that came with a new baseball podcast through Omaha Productions. Sources Tell Jeff Passan launched last month, built around the idea of making listeners feel like they understand baseball a little better after every episode. He appears to be doing the same with ABS during his frequent appearances on The Rich Eisen Show.