Baseball umpires are on their way out. But what will players, coaches, and fans do if there’s nobody to yell at?By Jack SullivanOn opening day last week, amid the sounds of bat on ball and the crunch of Cracker Jack, a death knell could be heard reverberating around baseball stadiums: A.I. was coming for the umpires.Why? Because human umpires are capable of error, and in professional sports, errors can mean the difference between winning and losing. So professional sports teams and athletes have been increasingly interested in automated referees that make no mistakes.This technology has been most effectively implemented in tennis, which, for nearly 20 years, has utilized Hawk-Eye technology—a band of high-speed cameras abetted, more recently, by A.I.—to judge whether balls are in or out.READ ON