Unwritten rules of baseball

[2] Since the beginnings of baseball in the 19th century, players have adopted unwritten rules about how to behave during the game.

[18] Stan Williams, a pitcher who played during the 1960s, wrote the names of players he felt he had to retaliate against on the inside of his baseball cap.

The next time they faced each other was four years later; they were teammates and Farmer hit Gross during batting practice to retaliate.

[21] Nolan Ryan adhered to the unwritten rules, and was known to retaliate for violations against other teams' players with beanballs.

[20][22] In 1994, while playing in Minor League Baseball, Michael Jordan violated the unwritten rules by stealing third base even though his team had an 11–0 lead.

Ben Davis bunted against Curt Schilling during a potential perfect game in 2001, stirring controversy.

Pitcher Sam Dyson took offense to the bat flip and told Edwin Encarnación to tell Bautista to "respect the game".

[34] In a 2019 National League game between the Cincinnati Reds and Pittsburgh Pirates, Reds player Derek Dietrich stood at home plate and admired a home run off pitcher Chris Archer, which bounced out of the stadium and into the Allegheny River.

The Pirates felt he admired it for too long of a time, and Archer threw behind him on his next at-bat, sparking a brawl that resulted in the ejections of four players and Reds manager David Bell.

[35] In 2020, Fernando Tatís Jr. of the San Diego Padres was accused of breaking an unwritten rule in a game against the Texas Rangers when he swung at a 3–0 pitch with the bases loaded when his team was leading by seven runs in the eighth inning.

The following day, in another game against the Rangers, Tatís allegedly broke another unwritten rule by stealing third base when his team was leading by six runs in the fourth inning.

[36] In 2021, rookie Yermín Mercedes of the Chicago White Sox was accused by his own manager of breaking an unwritten rule in a game against the Minnesota Twins.

[39] In 2018 MLB launched a marketing campaign called "Let the Kids Play", which explicitly criticized the unwritten rules concerning bat flips and player celebrations.