Though I'm curious about this in all sports, I'll limit my question to the scope of MLB for the moment. My question is what (if any) are the rules regarding electronic assistance in baseball games?


  • Scenario 1: Player batting has a ear bud inside his ear that is receiving info from another party in real time about where the catcher is located; what pitch to expect; etc.
  • Scenario 2: Pitcher is wearing ear bud and receiving information about where this player likes pitches, his weak spots, how he does in certain counts; etc.
  • Scenario 3: Manager receives real time data about whether to challenge a call based on a team of people scouring instant replay video.

Scenario 1 seems like it is obviously illegal, and should be.

Scenario 2 is no different than what pitchers do to prepare before games and perhaps between innings; but it allows for a much finer control on a pitch by pitch basis - and for some reason feels like it should be illegal.

Scenario 3 is legal and practiced.

So with that as background; my question expanded is:

Are there any rules governing this?

If so:

  • What are they?
  • And given the vast array of potential uses for electronic assistance in the game, what are the guiding principles in determining legality in a given situation?
  • 1
    Coincidentally, with sign stealing by runners #1 happens, albeit more challenging... and I wonder whether it would be possible for a relay system where the clubhouse sends pitch-by-pitch strategy to the dugout which sends it on to the catcher\pitcher. So certainly an interesting question you ask, with a lot of possibilities. Aug 1, 2016 at 0:14
  • 1
    @JeopardyTempest - right. That's what made me think of it. Though sign stealing has been around since the beginning, it hasn't really been such a big deal because it's really hard. Imagine though an algorithm to calculate the coach signals prior to each play, discovering fake signs, etc. Then send a vibration to a wristband or something like that. You can imagine it could get quite precise.
    – dgo
    Aug 1, 2016 at 0:41
  • 1
    With all the attention to little advantages, and the growth of sabermetrics, I'm surprised it hasn't been a focus yet. Then again, if you do it, you probably don't talk about it. And with scandals such as taping opposing team practices and deflating footballs... you'd think someone were at least thinking about it... Especially if you consider the wider picture of play calling... like some of the fastpaced college football teams that relay plays directly from the sideline... no huddle in the NFL... and NBA plays. Aug 1, 2016 at 2:32

1 Answer 1


There is no official MLB rule against electronic devices. No phrase related with electronic devices is found in Official Baseball Rules 2015 Edition.

However, Sandy Alderson, MLB operations chief in 2000, effectively laid down the law with a memo that states:

Please be reminded that the use of electronic equipment during a game is restricted. No club shall use electronic equipment, including walkie-talkies and cellular telephones, to communicate to or with any on-field personnel, including those, in the dugout, bullpen, field and-during the game-the clubhouse. Such equipment may not be used for the purpose of stealing signs or conveying information designed to give a club an advantage. (emphasis mine)

  • Funny that in scenario 3 of my question this seems to be directly violated. Probably this rule should be included in the official rules and be worded very clearly, because I can still imagine loopholes. Good answer though.
    – dgo
    Aug 15, 2016 at 2:47
  • @user1167442 I think you are confused. They use a fixed line to communicate with a bullpen and it doesn't violate anything and neither does your No. 3 scenario.
    – user10632
    Aug 15, 2016 at 7:10
  • It's likely that I'm confused. It's happened before. I think I have enough resources though to un-confuse myself. Thanks
    – dgo
    Aug 15, 2016 at 15:26

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