Coming April 2027

MLB referee reports

The home-plate umpire's zone is the purest official-impact story in sport. We will read it before first pitch, not grade it after the final out.

01 · The card

MLB reports start in April 2027. Until then, here is what we will measure and why. The methodology is published before the first read.

02 · What we measure

• Zone Expansion Index

  How much bigger or smaller tonight's plate umpire calls the zone than the rulebook, before the game.

• Pitcher-Umpire Match

  How tonight's starter's pitch mix plays into this umpire's zone.