What do the official rules actually say?
There is so much confusion out there about what is and what isn’t allowed, so let’s get the rules straight about what, when, and how is it legal or illegal to “steal signs,” according to the rules.
First of all, there is no rule prohibiting the stealing of signs. It’s actually a common and generally accepted practice in the game, and it has been for decades. Even Ty Cobb wrote in 1926 that, “If a player is smart enough to solve the opposing system of signals he is given due credit.”
To expand on that, Dave Campbell wrote:
"“However, it is fair game to steal signs from second. The runner at second can look in at the catcher’s signals in an attempt to decipher what the catcher is calling, or he can lean in to determine the location of the pitch. While standing on second base, veteran ballplayers can subtly pass the information they decipher along to the hitter. This is simply considered gamesmanship — no one would think of it as cheating.”"
The dividing line lies in the use of mechanical or technological devices to steal signs. Stealing signs with the naked eye is fine, but using additional help is what is frowned upon. The National League banned the use of mechanical devices to steal signs in 1961, and then-MLB Vice President Sandy Alderson issued a memo in 2001 advising teams that the use of electronic equipment to steal signs was prohibited.
In February 2019, Commissioner Rob Manfred circulated a five-page memo enforcing existing sign-stealing rules and outlining new ones, specifically where cameras could be positioned, assigning security experts to monitor team managers who have access to live game feeds for the purposes of challenging a call on the field, and requiring an eight-second delay on all other TV monitors viewed during the game by players and coaches in the bullpen or the clubhouse.
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. To be clear, the Red Sox were fined not for deciphering signs, but because of the use of an electronic means of communicating these signs to each other.
Boston then accused the Yankees of stealing signs using a television camera from the YES television network, which is partially owned by the Yankees. The investigation by MLB did not turn up any evidence to support the allegations made by the Red Sox but instead found evidence of improper use of the dugout phone in an earlier championship prior to 2017. Because the phone was an improper electronic means to communicate, the Yankees were also fined for violation of the rules governing the use of electronics.