The Origin - The Runner on Second
The most primitive form of sign stealing involves a runner on second base reading the catcher's signs and relaying pitch type to the batter. From second base, the catcher's signals to the pitcher are visible head-on, enabling runners to communicate via gestures or verbal cues. This practice has existed since baseball's earliest days and was tacitly tolerated as cerebral play rather than rule violation. Catchers developed countermeasures by complicating sign sequences, designating only specific positions within a series as the live signal. Even today, catchers routinely change sign patterns with runners on second.
Technology Intervenes - From Telescopes to Video
Sign stealing became criminal when technology entered the equation. In 1951, the New York Giants used a centerfield telescope to steal catcher signs, relaying them to batters via buzzer. The Giants erased a 13.5-game deficit that season, and the Shot Heard Round the World home run may have been aided by stolen signs. In Japan, telescope-based sign stealing from scoreboard rooms and bullpens was rumored at multiple teams through the 1990s and 2000s. Video technology enabled real-time sign decoding and relay, transforming sign stealing from individual skill into organized institutional fraud.
The Astros Scandal
The 2017 Houston Astros scandal brought sign stealing to global attention. The Astros used a centerfield camera to capture catcher signs, displayed them on a bench monitor for real-time decoding, and relayed pitch type by banging a trash can: bangs for off-speed, silence for fastballs. Exposed by a 2019 whistleblower, the scandal resulted in the manager and general manager's firing, a five-million-dollar fine, and draft pick forfeiture. However, no individual player was punished and the 2017 World Series title stood, drawing fierce criticism. The scandal catalyzed MLB's regulatory crackdown on technology-assisted sign stealing.
Sign Stealing in NPB
NPB has faced recurring sign stealing issues. In 2015, the Yomiuri Giants were suspected of stealing catcher signs from the bench and relaying them to batters through block signals. NPB investigated but issued no definitive punishment. High school baseball has long struggled with runner-based sign stealing, and the federation explicitly prohibits runners and base coaches from stealing and relaying signs, though enforcement in live games remains difficult. Since 2020, NPB has tightened regulations on in-bench video equipment, restricting real-time footage access during games. However, technology tends to outpace regulation, with wearable devices and vibration-based relay methods raising new concerns.
Encrypted Signs - PitchCom and the Future
MLB introduced PitchCom in 2022 as a fundamental solution. The system allows catchers to select pitch type and location on a handheld device, transmitting audio to the pitcher's earpiece. Electronic encryption makes visual sign stealing theoretically impossible, and sign-stealing allegations have plummeted since adoption. NPB has not implemented PitchCom as of 2024 but is evaluating it. Cautious voices cite equipment malfunction risks, radio interference, and the traditional view that sign gamesmanship is part of baseball. Yet as technology continuously advances offensive sign-stealing capabilities, technological defensive countermeasures are inevitable. The history of sign stealing demonstrates that baseball's definition of fairness evolves with each era.