Baseball rules

[2] WBSC rules are largely similar to the OBR, with minor differences including pitch clock timing and extra-innings tiebreakers.

The baseball rulebook of the National Collegiate Athletic Association (NCAA), aside from governing the games of that organization's members, is also used by several other competitions involving college-aged players.

The modern game began to take shape in the late 1880s, with additional significant rule changes made during the rest of that century.

Due to the frequent and often radical rule changes during this early period, the "modern era" is generally considered to have begun in 1901, when the American League was also formed.

Until 1929 (AL) and 1931 (NL), a ball that bounced over the outfield fence in fair territory was a home run, not a ground rule double.

The pitcher throws pitches the ball towards home plate, where the catcher for the fielding team waits (in a crouched stance) to receive it.

In an enclosed field, a fair ball hit over the fence on the fly is an automatic home run, which entitles the batter and all runners to touch every base and score.

The locations of the other seven fielders are not specified by the rules, except that at the moment the pitch is delivered, they must be positioned in fair territory and not in the space between the pitcher and the catcher.

These are the two fielders who always deal directly with the batter on every pitch, hence the term "battery", coined by Henry Chadwick and later reinforced by the implied comparison to artillery fire.

Together with the pitcher and coaches, the catcher plots game strategy by suggesting different pitches and by shifting the starting positions of the other fielders.

Catchers are also responsible for defense in the area near home plate (such as dropped third strikes and wild pitches) or baserunning plays, most commonly when an opposing player attempts to steal a base.

This position is the most demanding defensively, so a good shortstop doesn't need to necessarily be a skilled batter, though this has changed in modern times.

Quick reaction time is also important for third basemen, as they tend to see more sharply-hit balls than do the other infielders, thus the nickname for third base as the "hot corner".

Also, because there are far more right-handed hitters than lefties, there are more ground balls hit to the left side of the infield due to the natural motion of the batter's swing.

The right fielder generally has the strongest arm of all the outfielders due to the need to make throws on runners attempting to take third base.

The center fielder has more territory to cover than the corner outfielders, so this player must be quick and agile with a strong arm to throw balls into the infield; as with the shortstop, teams tend to emphasize defense at this position.

Of all outfielders, the left fielder often has the weakest arm, as they generally do not need to throw the ball as far in order to prevent the advance of any baserunners.

In baseball's early years, squads were smaller, and relief pitchers were relatively uncommon, with the starter normally remaining for the entire game unless he was either thoroughly ineffective or became injured.

While delivering the ball, the pitcher has a great arsenal at his disposal in the variation of location, velocity, movement, and arm position (see types of pitches).

Common pitches include a fastball, which is the ball thrown at high speed; a curveball, which is made to curve by rotation imparted by the pitcher; a change-up, which seeks to mimic the delivery of a fastball, but arrives at significantly lower velocity; a splitfinger fastball, which attempts to mimic the delivery of a fastball, but has slight topspin rotation allowing the baseball to sink as it approaches the batter due to the position of the index finger and middle finger being "split" on the baseball; a slider, which is made to curve laterally by rotation imparted by the pitcher; a knuckleball, which is held either by the knuckles closest to the nails or by the nails themselves letting the pitcher throw a baseball with little or no spin on the ball allowing the baseball to move in any direction; a Vulcan changeup, which seeks to mimic the delivery of a fastball, but arrives at a significant lower velocity due to the pitcher holding the baseball with the middle and ring fingers slightly apart; a circle changeup, which is held in the palm of the hand with the index finger curled around the side of the baseball, allowing the pitcher to mimic the delivery of a fastball, but arrives at a significantly lower velocity.

Changes to the lineup are tightly limited by the rules of baseball and must be communicated to the umpires, who have the substitutions announced for the opposing team and fans.

The pitcher, in lieu of delivering the pitch, may try to prevent this by throwing the ball to one of the infielders in order to tag the runner; if successful, it is called a pick-off.

These clues (also referred to as "tipping pitches") include movements of the pitcher's arms, shoulders, body, etc., or the positioning of the catcher's feet and glove.

In general, base running is a tactical part of the game requiring good judgment by runners (and their coaches) to assess the risk in attempting to advance.

(Noted exceptions to the dangerous contact rule are found throughout amateur competitions, including youth leagues, high school, and college baseball.)

In Major League Baseball, games end with tie scores only in rare cases when conditions make it impossible to continue play.

Previously, curfews and the absence of adequate lighting caused more ties and shortened games—now, games interrupted from ending in such circumstances are, at least initially, suspended.

Later in the game, after Musial had faced one batter, the players switched back, with Haddix relieving the outfielder-turned relief pitcher.

Many amateur leagues allow a starting player who was removed to return to the game in the same position in the batting order under a re-entry rule.

Beginning in the 2012 season, a major league team was allowed to carry a 26th man on its roster when playing the second game of a double-header that was scheduled at least 48 hours in advance.