What Does it Mean to Steal Signs in Baseball?

A brief history of sign stealing in baseball.

The Boston Red Sox have reportedly been accused of using an Apple Watch to steal signs from the New York Yankees, according to a complaint filed to the commissioner's office by Yankees general manager Brian Cashman.

MLB investigators are looking into claims that the Red Sox used the watches to steal hand signals from opponents' catchers. The watches would tell them what type of pitch was being thrown, information which would be relayed to players. 

The report comes just a few weeks after commissioner Rob Manfred said that he's had complaints from players about sign stealing and how it impacts the pace of play with men on base. He described sign stealing as "a form of behavior that we should not tolerate" and there are rules that would regulate the use of electronic devices being used.

How does sign stealing work? It depends on the era. Sign stealing, which consists of one team intercepting the hand signals of another team, has been a part of baseball for many decades.

In 1951, the Wall Street Journalreported that the New York Giants used a telescope from center field to read signs from opposing catchers. Information was sent to Giants players from a player in the bullpen. This is the same year that Bobby Thompson hit the "Shot Heard Round the World."

As technology advanced, so have the methods of cheating. In 1997, the New York Mets were accused of using a small camera near home plate in Shea Stadium to peek at catchers. They denied the allegations and were never punished by the league. In 2011, the Philadelphia Phillies were accused of stealing signs when other teams complained that they used binoculars to watch the opposing teams' catchers.

To an extent, instant replay video has also helped teams catch onto signs and trends from catchers and pitchers. Former Major League manager Jackie Moore previously told MLB.com that teams would sometimes create their own home field advantage.

"And the White Sox, years ago in their scoreboard, they'd have a light in their scoreboard in Chicago at the old ballpark," Moore said. "They'd have a guy in the scoreboard with binoculars. If it was a breaking ball, off-speed pitch, a light would come on. And about the only person who could see it would be the hitter. Because he was looking right over the pitcher's head and the center fielder's head and you could see the little small light come on."

The only punishment in the past for one team suspecting another of stealing signs has been an opposing hitter getting beaned with a pitch. Manfred and the league have yet to announce any new discipline to eliminating sign stealing, but the Red Sox and the Apple Watch allegations could change that.