It began as a way to tell a better story. A small, semi-transparent rectangle floating in midair above home plate, first rolled out by ESPN in 2001, showed something approaching the strike zone of a Major League Baseball player. As a flat, rigid representation of a fluctuating and notional three-dimensional space, it wasn’t perfect. But it gave viewers some sense of what players, pitchers and umpires were figuring out in real time: What counts as a ball and a strike in the most subjective of all spectator sports?
Armed with footage of strike calls that sailed wide of the supposed mark, supplemented by cameras wedged into the masks of umps and catchers, commentators had proof of umpires’ tendencies to expand or contract the plate. To be sure, it was an improvement. Compared to the cheesy comet-tails that NBC began editing into slo-mo pitch replays in the ‘80s, ESPN’s ghostly “K-Zone” felt deadly serious: a technological marvel for an objective, computer-assisted age.
