There are some rules in Major League Baseball that have "evolved" over time. One such example is the checked swing rule. Announcers talk about the bat "breaking the plane of the plate" to judge whether or not the batter checked his swing. The official MLB rules, however, say that a strike should be called if the hitter made an attempt to hit the pitch. It makes no mention of an imaginary "plane" that the bat must not break, yet it is common that this imaginary delimiter is used.

What other "traditions" like this exist in Major League Baseball that are not in the official rules, but have existed for so long that they are treated as such?

8 Answers 8


There is an interesting unwritten rule that actually gets contradicted in the official MLB rules. The "tie goes to the runner" claim is one that most baseball fans have heard.

Rule 6.05j states that "a batter is out when after a third strike or after he hits a fair ball, he or first base is tagged before he touches first base."

So in this case the rules claim the ball must arrive first. Giving the tie to the runner.


Rule 7.08e states that "any runner is out when he fails to reach the next base before a fielder tags him or the base"

In this case it is the runner that must reach the base before the ball, giving the tie to the defensive team.

So the tie goes to the runner, you know, sometimes or something.

  • 1
    In the eyes of many umpires, a tie actually goes to the fielder. The rationale is that the umpire makes his judgment by comparing the sound of the ball hitting the glove with his view of the runner's foot hitting the bag. Because sound travels much slower than light, if the sound is perceived at the same time as visual contact, then the ball actually got there first and the runner is out. Commented Jun 28, 2013 at 16:34
  • Even if the umpire stood 20 meters away, it would only take the sound 0.06 seconds to reach him. How many are within about 1/20th of a second?? Commented May 21, 2017 at 10:59
  • Stand 20 meters away from someone and have them clap. Tell me if their sound is behind the appearance? :-D This article suggests our brain tries to automatically sync sight and sound (best I could find, sight process time estimates are 0.01-0.1 seconds to process, audio is about 0.05? Not enough to significantly alter the minor lag calculated, but still, it's shrinking even further. Commented May 21, 2017 at 11:05
  • @JeopardyTempest I think you're underestimating just how long 1/20th of a second is. Think about it this way: it takes the average batter a little over 4 seconds to get from home to first (90 feet). Call it 4.5 seconds. That means it's taking them 1/20th of a second to travel each foot. How many plays are decided by a foot (i.e. in how many is the batter/runner a foot or less away from first when the throw is received?) - a lot, right?
    – Jer
    Commented Jun 21, 2017 at 19:36
  • I don't know, hasn't tv traditionally only been 30 fps (not counting interlacing)? So you're talking about a 1-2 frame delay... for an ump standing 60 feet away. Commented Jun 22, 2017 at 1:24

A few that come to mind:

  1. The "neighborhood play" at second base, where the fielder doesn't actually touch second base during a double play attempt.

  2. Batters going to first base if a pitch that they made no effort to get out of the way of hits them. According to the rules, a batter must attempt to get out of the way of a pitch.

  3. An outfielder using the wall itself as support when trying to catch a would-be home run. This doesn't happen often but it's against the rules to boost yourself up using the wall. I have never seen this called as a home run when the fielder catches the ball.
  4. Of course, the strike zone.

I'd also add another version to your example - I often hear that it's a check swing if the batter didn't "break" (i.e. turnover) his wrists.

  • These aren't what we're typically talking about when we talk about unwritten rules. Usually what we're thinking of is beaning an opposing player when one of your guys get hit, not showboating after a homer, that kind of thing.
    – wax eagle
    Commented Aug 10, 2013 at 2:31
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    @waxeagle - I agree that they're not "unwritten rules" - however I think it's exactly what the question was asking for (see the example given in the question about check swings). Perhaps the question can be edited to refer to "rules that have become customary despite not being in the rule book."
    – Jer
    Commented Aug 12, 2013 at 16:07
  • 1
    You're right. Good edit on the question. I'm going to edit your answer to remove the downvote
    – wax eagle
    Commented Aug 12, 2013 at 16:55
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    Update: as of 2016 the "neighborhood play" has been banned in the major leagues. The fielder must actually touch the base while in possession of the ball in order to put the runner out. Commented May 1, 2016 at 15:50

There are a bunch of "Unwritten Rules" for example you don't steal when you have a large lead, don't put your bat on the plate after a walk, a runner shouldn't run over the pitching mound when going back to their dug out after an out. These are generally silly ideas and almost a type of etiquette.

  • 1
    This is more of an example of sportsmanship or superstition, which is different than what I was referring to in my original question.
    – MDMarra
    Commented Oct 9, 2012 at 20:09
  • That's odd, because this is exactly what we think of when we talk about baseball's unwritten rules.
    – wax eagle
    Commented Aug 10, 2013 at 2:32
  • Again - I agree with @MDMarra - though I can see interpreting the question that way if you don't read the body of the question.
    – dgo
    Commented Oct 4, 2016 at 12:53

To add to Hennish's list, don't bunt when you have a large lead. Bunting is a strategy to gain advantage. When you clearly have an advantage is gives a bad impression.

  • This is more of an example of sportsmanship, which is different than what I was referring to in my original question.
    – MDMarra
    Commented Oct 9, 2012 at 20:09

We used to call "The neighborhood play" "The Phatom double". It was allowed when the runner from first was attempting a break up.

  • 3
    So, "The neighborhood play" was also called the "The Phantom Double", or do both have the same meaning? Or are they two "rules" that were called when the runner from first was attempting to break up? Perhaps you can edit your answer and add some references as well. Welcome to Sports Beta !!
    – Jacob Jan
    Commented Oct 5, 2013 at 21:12

A lot of what is listed here: Baseball's 25 Biggest Unwritten Rules is more about sportsmanship but the article (even if it is a bunch of slides) seems to be cited elsewhere several times. Also cited elsewhere is this: The Book of Unwritten Baseball Rules which lists a bunch of "unwritten rules" most of the first article repeats, but once again deals a lot w/ sportsmanship.

  • With a right-hander on the mound, don't walk a right-handed hitter to pitch to a left-handed hitter
  • Never mention a no-hitter while it's in progress.
  • A manager should remain detached from his players.
  • Hit the ball where it's pitched.
  • If one of your players gets knocked down by a pitch, retaliate
  • Hit behind the runner at first.
  • 2
    This is cool - but as mentioned - I think this is more in the spirit of "accepted orthodoxy" than unwritten rules as asked by @MdMarra
    – dgo
    Commented Oct 4, 2016 at 12:54

There are seemingly ironclad rules regarding handedness and position. For example, there are no left handed throwing 2B,SS,3B or C.


It is in the rules and it is called a half swing. In the index it is listed as checked swing.

Rule 9.02(c)

The manager or the catcher may request the plate umpire to ask his partner for help on a half swing when the plate umpire calls the pitch a ball, but not when the pitch is called a strike. The manager may not complain that the umpire made an improper call, but only that he did not ask his partner for help. Field umpires must be alerted to the request from the plate umpire and quickly respond. Managers may not protest the call of a ball or strike on the pretense they are asking for information about a half swing. Appeals on a half swing may be made only on the call of ball and when asked to appeal, the home plate umpire must refer to a base umpire for his judgment on the half swing. Should the base umpire call the pitch a strike, the strike call shall prevail.

Crossing base line seems to be the common interpretation.

  • Wow not even going to ask on the down vote.
    – paparazzo
    Commented Jun 20, 2018 at 20:09

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