Flat bats, spitballs, and a ban on licorice: 10 of the weirdest rules in baseball history

In pre-Knickerbocker-rules baseball, different regional styles would have fielders "soak" or "plug" the baserunner, which meant hitting them with the ball and resulting in an out. This was used in the New England regional variant known as the "Massachusetts Game" and others, per the Baseball Almanac.

Though this added an extra contact element to the game, the ball was lighter than it is today and featured a softer leather surface.

This practice was outlawed in the Knickerbocker rules, in which a fielder had to tag the runner for an out.

Pitchers originally had to throw underhand in the Knickerbocker rules, likely drawing inspiration from cricket players' "underarm bowling" techniques at the time. The Knickerbocker rules made a distinction between pitching and throwing, noting, "The ball must be pitched, not thrown, for the bat."

The rule stood in leagues for a few decades until changes allowed pitchers more freedom. According to the Baseball Almanac, the National League allowed pitchers to throw sidearm in 1882, and then with no limitations at all in 1884.

Per the original Knickerbocker rules, games were played until a team scored 21 runs, called "aces" at the time. This meant the length of games could vary substantially, and it was possible for a team to win with 21 runs without their opponents even getting to the plate.

Because of the rule, long games would sometimes end prematurely due to darkness, and it wouldn't be until 1935 that the first night game under electric lights would be played in the major leagues, according to the National Baseball Hall of Fame.

As a result, the 9-inning standard we know today was implemented into the Knickerbocker rules in 1857.

Contrary to the basic fundamentals of modern baseball, until 1864, the Knickerbocker rules allowed for fielders to catch the ball after one bounce or "bound" for an out.

In foul territory, the rule still stood until 1882, when it was changed to a regular fly-ball out by the National League.

While a batter getting to choose the type of pitch they want seems unheard of in today's game, it was once standard practice.

For roughly 20 years, the batter was required to request a "high," "low," or "fair" pitch upon coming up to bat. The pitcher would then have to throw accurately to this demand. The rule was disallowed in 1886.

The history of balls and strikes wasn't always straightforward. Umpires would initially call "fair" and "unfair" pitches before strikes were introduced in 1858 and balls in 1863, per MLB.com. However, it took a whopping nine called balls before a batter would be sent to first base.

The number of called balls was gradually lowered in the National League until it became four in 1889, where it has stood ever since.

From 1885 to 1893, the National League allowed for the use of bats with a flat side. Players would mostly utilize the paddle-like bats for bunting, according to ESPN.

Though flat bats were eventually banned, baseball would see plenty of new, sometimes weird advancements in bat technology. Heinie Groh of the New York Giants hit with a "bottle bat," notable for its large barrel. And in 2025, the Yankees set a trend around the MLB with their "torpedo bats," which distribute the wood's weight in a favorable way for the hitter.

A "spitball" is exactly as it sounds. Pitchers used to be allowed to lubricate the ball with saliva to get a better pitch.

While players did literally use their own spit, the term also applies to any foreign substance applied to the ball, such as mud or petroleum jelly. The pitch reached peak popularity in the early 20th century, and safety concerns led to its ban in 1920, per Twins Daily.

Oddly, the MLB still allowed 17 legacy "spitters" to continue to throw the pitch until their retirement. Pitcher Burleigh Grimes played in the major leagues until 1934, using the spitball until the day he retired.

In the current MLB rulebook, a provision notes, "No player shall intentionally discolor or damage the ball by rubbing it with soil, rosin, paraffin, licorice, sand-paper, emery-paper or other foreign substance."

Thanks to the legacy of the spitball, there's now an official rule against licorice in the MLB.

In the current MLB rulebook, a quirk exists under the "Security" section, which provides guidelines on stadium protection and the procedure for when a person or group enters the playing field during a game.

The penalty in the section reads, "If the field is not cleared in a reasonable length of time, which shall in no case be less than 15 minutes after the visiting team's refusal to play, the umpire-in-chief may forfeit the game to the visiting team."

Even if such a scenario were to occur, it would be more likely that the game would be suspended and completed at a later time, as is commonly the case with rain delays. Alternatively, games suspended after 5 innings can be deemed "official," with the current score standing as the final result.

Still on the books today, the MLB rule on "Fraternization" states, "Players of opposing teams shall not fraternize at any time while in uniform." Perhaps the most unenforced rule in the major leagues, it's broken on a nightly basis.

The rule also disallows players from interacting with spectators during or after a game. This means that anytime a first baseman tosses a foul ball to a wide-eyed kid in the stands, it's technically in violation of the MLB rulebook.