Sign of times: MLB gives OK to electronic pitch calling - NBC Sports
Push-button pitching: MLB to let pitchers call own signals – NBC
Sign Of Times: MLB Gives OK To Electronic Pitch Calling
MLB to allow electronic pitch-signaling devices in 2022 season to
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Sign Stealing - 99% Invisible
Pitch Clocks, Shift Limits, Larger Bases In MLB's Future
MLB is turning to an electronic pitch-calling system to fight cheating
Sign stealing - Wikipedia
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Sign of times: MLB approves use of anti-sign-stealing technology