Baseball’s unwritten rules are a code of conduct players enforce among themselves, covering sportsmanship, respect and superstition. They are not in any rulebook, but breaking them has sparked benches clearing brawls and pitches thrown at batters for more than a century. Many are fading as a new generation celebrates more openly.
The Unwritten Rules
| Rule | What it means | Notes |
|---|---|---|
| Don’t bunt to break up a no hitter | Especially late in a close game | Seen as cheapening the moment |
| Don’t steal with a big lead late | Usually a lead of seven or more runs in the late innings | Viewed as running up the score |
| Don’t swing 3 and 0 with a big lead | Take the pitch in a blowout | A frequent flashpoint for retaliation |
| Don’t mention a no hitter in progress | Teammates stay away from the pitcher in the dugout | A superstition, not a strategy |
| Don’t admire a home run | Avoid long stares and slow trots | Far more accepted now than a decade ago |
| Don’t walk across the mound | Especially while the pitcher is warming up | Seen as disrespecting his space |
| Don’t show up a teammate | No visible frustration at a fielder’s error | |
| Don’t peek at the catcher’s signs | As a hitter, don’t look back | A pitch aimed inside may follow |
| Protect your teammates | If a star is hit, the other team’s star may be hit back | Umpires issue warnings to stop it |
| Don’t slide spikes up | Slide to the base, not the fielder | Some slides are now banned by rule |
| Don’t step on the foul line | Many players hop over it | Pure superstition |
| Don’t celebrate a strikeout too loudly | Pitchers keep it in check against veterans | Also fading with the times |
The Code Is Changing
Bat flips, fist pumps and big celebrations that once guaranteed a fastball in the ribs are now part of the game’s marketing. MLB has leaned into player personality, and many younger players see the old code as outdated. The rules about safety, like sliding and not throwing at heads, have become official rules, while the rules about showmanship have faded the fastest.
For the language players use on the field, see the baseball slang glossary.
Related
Baseball slang glossary · No hitter vs. perfect game · What is a walk off
Rules on retaliation and warnings from the MLB official rules.