In baseball, sign stealing is the observing and relaying, through legal and illegal methods, of the signs being given by the opposing catcher to the pitcher. The signs are relayed to the batter to give advance knowledge of what kind of pitch is coming next, thereby giving that batter an advantage. Legal sign stealing typically involves the signs being observed by a runner on second base and then relayed to the batter through some sort of gesture. Illegal sign stealing involves mechanical or electronic technology; the rules regarding this have become more stringent over time and continue to evolve.
According to the unwritten rules of baseball, stealing the signs that are given by the third base coach, or those of the catcher by a baserunner on second base, is acceptable, and it is up to the team giving the signs to protect them so they are not stolen. Even so, suspected sign stealing from second base may be answered with a brushback pitch. On the other hand, a batter peeking in to see the catcher's signs is definitely not tolerated. The signs the catcher sends to the pitcher to call for the next pitch are considered more "sacred" than the signs a third base coach relays to the batter.
Stealing signs is not necessarily a violation of Major League Baseball's (MLB) rulebook; it depends how the signs are stolen. At the December 1961 Winter Meetings, the National League banned the use of a "mechanical device" to steal signs. The use of electronic equipment is not specifically forbidden by MLB rules, but in 2001, Sandy Alderson, while serving as executive vice president for baseball operations of MLB, issued a memorandum stating that teams cannot use electronic equipment to communicate with each other during games, especially for the purpose of stealing signs. Before the 2019 season, Rob Manfred, the commissioner of baseball, instituted specific prohibitions on where teams could position cameras and how instant replay officials can communicate with managers in an effort to reduce illicit sign stealing.
The oldest recorded instance of a team attempting to steal signs dates back to 1876, when the Hartford Dark Blues hid a person in a shack to tip off their hitters when the pitcher would throw a curveball. In 1897, George Stallings, the manager of the Philadelphia Phillies, had Morgan Murphy, a backup catcher, hide in a clubhouse beyond center field with a binocular and a telegraph that he used to alert Stallings to what pitch the opposing catcher was calling. In 1900, Pearce Chiles, a coach for the Phillies, was caught standing on a box with electric wires that relayed to him coded messages about what pitch was coming, which he relayed to the batters by stomping on the ground. Del Baker, Joey Amalfitano, and Joe Nossek were considered to be among baseball's best sign stealers.
On May 26, 1959, despite the Milwaukee Braves bullpen stealing catcher Smokey Burgess's signs, Pittsburgh Pirate pitcher Harvey Haddix threw 12 perfect innings before losing the game in the 13th. The only Brave player not to accept the signs was Hank Aaron.
In 2001, members of the 1951 New York Giants admitted to stealing signs against the Brooklyn Dodgers using a telescope to win the National League that season. Bobby Thomson, who hit the "Shot Heard 'Round the World", denied being tipped off to that pitch. In March 1962, newly acquired Mets hurler Jay Hook accused his previous team, the 1961 National League champion Reds, of stealing signs throughout that season with the aid of former Reds pitcher Brooks Lawrence, stationed inside Crosley Field's scoreboard. Though Lawrence denied the charge, Reds manager Fred Hutchinson, when asked if he would either confirm or deny the allegation, replied simply, "No. No comment." 40 years later, Hook's story was indirectly corroborated by another member of the '61 Reds, pitcher-author Jim Brosnan, discussing the disappointing home field performance by Reds hitters during the 1961 World Series, despite having Lawrence "up in the left-centerfield scoreboard, stealing every sign the Yankee catchers gave." In 2017, the Boston Red Sox were caught stealing signs against the New York Yankees and relaying them using an Apple Watch, which was not allowed to be in the dugout. The incident resulted in a fine for the Red Sox and warning issued to all 30 teams concerning sign stealing. The same year, a phone conversation between Yankees pitching coach Larry Rothschild and replay room officials revealed that the Yankees did in fact engage in sign stealing with Apple Watch as well, which resulted in the Yankees also being fined.
After the 2019 season, Mike Fiers alleged that the 2017 Houston Astros used technology to illegally steal their opponents' signs and relay them to their hitters. MLB and the Astros opened an investigation into the allegation, and it was expanded to encompass the 2018 and 2019 seasons. On January 13, 2020, Rob Manfred announced that MLB's investigation confirmed that the Astros illegally used a video camera system to steal signs during their 2017 and 2018 seasons. The organization was penalized with a $5 million fine, forfeiture of first- and second-round draft picks in 2020 and 2021, and the suspension of general manager Jeff Luhnow and field manager A. J. Hinch for one year; Luhnow and Hinch were also fired by the team the same day. Three days after the Astros penalties were announced, the New York Mets parted ways with Carlos Beltrán, who had been hired as the team's new manager on November 1, 2019, before Beltrán managed a game. Beltrán, who had played for the Astros in 2017, was the only player specifically named in MLB's report on the Astros scandal. While he was not directly linked to any prohibited activity, he was one of several Astros players who met during that season to discuss sign stealing improvements.
On January 7, 2020, the Boston Red Sox were implicated in another sign stealing scandal after three unnamed team members told The Athletic that the Red Sox had used their replay room to steal signs of opposing teams during the 2018 season. On January 13, 2020, Manfred stated that he will determine the appropriate punishment for Red Sox manager Alex Cora, who was also implicated in the Astros scandal, when the investigation is completed. The next day, Cora and the Red Sox mutually agreed to part ways; Dave Dombrowski, the general manager who hired Cora, was dismissed from the Red Sox before the 2018 sign stealing scandal was made public.
On January 29, 2020, Masslive reported that the results of the MLB investigation against the Red Sox will be released before the start of training camp and as early as the following week. While the Astros and Red Sox continue in the spotlight, the Yankees were mentioned in the original story in The Athletic and are suspected by some observers. On February 4, 2020, MLB Network journalist Peter Gammons reported that former Red Sox player Chris Young told him that Young was the mastermind of the Red Sox Apple Watch scheme, telling him "I started the whole Apple Watch thing. I got it from when I was with the Yankees." Young later denied to SportsNet New York (SNY) that he told this to Gammons, and Gammons issued a retraction on Twitter complete with character compliment, calling Young "one of the great people who ever played" and saying that "[Young's] word is gold." In reporting Young's denial, however, SNY also revealed that Young had in fact been interviewed by MLB officials as part of the 2017 investigation against the Red Sox and that multiple sources told the sports news agency that Young was in fact a leader of the team's 2017 Apple Watch scheme.
On February 12, 2020, a person with knowledge of the probe, speaking on anonymity, told the Associated Press that the Red Sox investigation will take longer than expected and will not be concluded at the start of training camp as previously hoped. Dombrowski and Ron Roenicke, who served as bench coach during the 2018 season, were cleared of wrongdoing by MLB. On February 25, 2020, the MLB Players Association interviewed Red Sox players and coaches about the 2018 sign stealing scandal. On February 26, 2020, it was announced that the Red Sox investigation will not conclude at the end of the week as previously hoped.