Even the uninitiated know a few basic facts about the rules of baseball. Everyone knows the game is played on a diamond-shaped arrangement of four bases, and if the batter swings three times at the ball and misses, that player is out.

There is a lot more to the game that is known as America’s pastime, however. To fully master the sport, one must know regulations that extend from where the spectators observe the play, all the way down to the color of the umpire’s unmentionables.

Test your baseball expertise by studying the following strange rules and customs of the game.

No Strike Rule

As detailed in this post, there once was a time when batters were required to pitch in such a way that the batter would be able to hit the ball. Strikeouts did not occur.

No Hat Catching

Casting off a baseball glove and, instead, catching the ball in one’s hat is the epitome of coolness. It is also illegal. The rules prohibit manipulating the ball in any way with any part of a player’s uniform.

This rule not only puts the lid on hat catching, but it prevents a player from stopping a ball’s progress by throwing a glove or hat. Players used to do that to deflect a ball that was flying overhead too high to reach or to stop an out-of-reach ball from rolling past them.

If someone violates this rule, the penalty is that the batter and all runners on base get to advance three free bases. If the bases are loaded at the time, that gives the other side three runs and places the batter on third.

No Spitballs

Adding a dab of saliva to the ball is a favorite pitcher’s trick to make the ball harder to hit. Since the 1920s, that practice has been prohibited. Sweat, snot, or any other substance added to the ball is off-limits. This prohibition extends to sticky stuff, too. Pitchers still get into trouble today for adding pine tar to the ball to improve their grip for a powerful pitch.

Black to Basics

A popular legend is that the New York Yankees added stripes to their uniforms to make Babe Ruth look slimmer. While this cannot be positively confirmed, it is true that MLB umpires have a dress code that extends to where (hopefully) no one else will see. Umpires are required to wear black underwear. This rule is in place in case an umpire has a wardrobe malfunction in which the trousers split open from squatting or bending. Should this unfortunate occurrence take place, players and fans will hopefully be spared the distraction, since the black underwear should blend nicely with the umpire’s black pants.

The Ball Doesn’t Necessarily Have to Be Caught to Trigger an Out

If the batter hits a ball high into the air, it is known as a pop fly. If a player on the opposing team catches that ball, the batter is out.

There is one provision in the rules that will result in the batter being out, even if no one catches the ball. This is known as the Infield Fly Rule. Here’s how it works:

• A batter is up with fewer than two outs in the inning.
• There are runners on first and second base or the bases are loaded with runners on first, second, and third.
• The batter hits a pop fly that should be easily caught by an infielder.

When all of these conditions are met, the batter is out, even while the ball is still in the air. This is true, even if no one actually catches the ball.

The purpose of this rule is to prevent the defending team from intentionally dropping the ball to gain an advantage. Imagine, for example, that the bases are loaded, and the batter hits a pop fly toward third base. Without the Infield Fly Rule, the runners have a dilemma. If they stay close to their bases, the third base player could choose to let the ball drop and get multiple outs by tagging the runner who was on third, stepping on third base to force out the runner from second, and throwing to second base to force out the runner from first. If the runners go too far from their bases, the third base player catches the ball and doubles them off. The reason the rule applies only when at least first and second base occupied is that if there are not multiple runners on base, a missed popup can only result in one forced out.

Catching the Ball with a Catcher’s Mask

As previously noted, no part of the uniform can be used to manipulate the ball. Of course, this assumes the player intends to catch or stop the ball in this way. There is one situation that presumably no one would invite: catching the ball in the face.

This can happen when the catcher fails to catch the ball with his glove, and the ball strikes his or her face mask and gets stuck. If this happens (or if the ball gets stuck in any part of the catcher’s gear), all runners get to advance one free base.

This rule also holds true if the ball gets stuck in any part of the umpire’s uniform or gear.

Designated Hitters Don’t Have Designated Seating

A designated hitter may not sit in the bullpen unless he or she is serving as a bullpen catcher.

When You Are Hit, You’re Out

Presumably, no one wants to be hit by a ball, but it’s particularly bad if you are a runner. If the batter hits a ball that is in play, and if that ball hits a runner before being touched by the opposing team, that runner is out, whether he or she is in between bases or on base. The only exception is with the above-described Infield Fly Rule. In those situations, the runner is safe if hit by the ball while on base; if it happens in between bases, however, it is an out.

Ejected From the Game — Ejected From Uniform

If a player, coach, or manager is ejected from the game for bad behavior, that doesn’t mean he or she is ejected from the ballpark. The rules expressly permit an ejected player, coach, or manager to stay and watch the game from the spectator area, provided that he or she change out of uniform and into street clothes.

Pocket Authority

In the event of rainy conditions, the umpire has the authority to order the pitcher to put the rosin bag in his or her pocket.

No Pitch Switching, Unless….

Ambidextrous pitchers may not switch throwing arms in the middle of an at-bat. In other words, if the pitcher starts off using the right arm to pitch to a batter, he or she cannot switch to using the left arm until the next batter. The one exception is if the pitcher has injured an arm. If that happens, he or she may switch pitching arms, but there is no opportunity to warm up with the new pitching arm.

Hitting One Player Causes Another to Be Out

If there are two strikes on the batter, and a runner steals home, and the pitch hits the runner in the strike zone, the batter is out. The run does not score if there are two outs; if there are less than two outs, it does.