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Balls and strikes were called by a computer, not an umpire, at a professional baseball game this week

AP Photo/Eric Risberg
Eric Byrnes gestures while using a computerized video system to call balls and strikes at a game between the San Rafael Pacifics and Vallejo Admirals.
By Steve Mollman
Published Last updated This article is more than 2 years old.

A small, but notable moment in baseball history occurred this week. In a US minor-league game between the San Rafael Pacifics and Vallejo Admirals, the home plate umpire did not call balls and strikes. Instead, a computerized video system was used to make the determinations, which were relayed by the game’s announcer to the crowd cheering on the home team—and checking out the system’s performance—at Albert Park in San Rafael, California.

The system, Pitchf/x from Chicago-based Sportvision, isn’t new to baseball. It already provides data for evaluating players and umpires, and it helps TV viewers see where a pitch lands relative to the strike zone. But on July 28 it was used to make actual calls, marking the first time that’s happened in professional baseball.

Eric Byrnes, a player turned commentator who proposed the idea to the San Rafael Pacifics, noted the moment on his Instagram account:

The system isn’t perfect for making calls—not a surprise since it wasn’t designed for that in the first place. It uses three cameras to triangulate a ball’s position in the air, but stops tracking a few feet before the plate, instead analyzing the trajectory to determine a predicted location within an inch of where the ball actually shows up.

That means that, for now, fans will have to decide for themselves which kind of error they prefer: human or computerized.

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