For baseball fans, the ABS challenge system has been one of the most exciting developments this season—and ESPN MLB insider Jeff Passan has become the go-to source for understanding how it all works. He's been tracking this story for years, dating back to his appearances on The Rich Eisen Show in 2024, where he argued that automated ball-strike technology was the only real fix for a broken umpire accountability system. Now that ABS is actually here and thriving, Passan continues to offer the clearest insights into its inner workings.

In a recent conversation with Eisen, Passan revealed a fascinating detail that most fans don't know: umpires now have a two-way microphone connecting them to the ABS operator during games. If a home plate umpire's strike zone starts to drift, someone can alert them in real-time—mid-game, mid-inning—to correct course. "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."

This marks a significant shift from baseball's recent history, where umpires were graded on a curve wide enough to make almost everyone look competent, and the union shielded them from meaningful public accountability. When Ángel Hernández finally retired in 2024, Passan noted that public pressure from fans and media had done what the league's own system never could. Now, it seems ABS has been quietly doing the same thing—pitch by pitch, without anyone realizing it until this week.

Passan, who re-signed with ESPN in March on a multi-year deal that includes a new baseball podcast through Omaha Productions, launched "Sources Tell Jeff Passan" last month. The show is built around helping listeners feel like they understand the game a little better—and with revelations like this, he's certainly delivering on that promise.