BASEBALL RULE CHANGES

A Timeline of Major League Baseball Rule Changes | Baseball Almanac

The rules have evolved from the original Knickerbocker Rules in 1845, to the first set of National League rules in 1877. Since those years, some major changes and rule additions have taken place and Baseball Almanac has, hopefully, listed them into an easy to understand timeline.

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Knickerbocker Rule Changes

In Chronological Order

1857 The game used to end after the inning in which a team reached 21 runs.
Now it is a 9-inning contest and the higher scoring team wins.
No base can be made on a foul ball.
1858 Called strikes are introduced.
A batter is out on a batted ball, fair or foul, if caught on the fly or after one bounce.
1862 Pitcher's box introduced' 12 feet by 3 feet.
1863 Bat size is regulated.
Called balls and bases on balls introduced
Pitcher's box is now 12 feet by 4 feet.
The pitcher is no longer allowed to take a step during his delivery and he had to pitch with both feet on the ground at the same time.
Home base and pitcher's box must be marked.
1862 Each base runner must touch each base in making the circuit.
1864 Out on a fair bound is removed and the "fly catch" of fair balls is adopted.
1866 Pitcher's box narrowed to six feet wide.
1867 Pitcher is now permitted to move around inside their box.
1868 Bat length limited to 42 inches.
Pitcher allowed to lift feet when delivering the ball.
Pitcher's box is now made into a 6 foot square.
1870 The batter-runner may overrun first base.
1871 The batter is officially given the privilege of calling for a low or high pitch (in practice since 1864).
1872 Ball size and weight are made smaller, to dimensions currently in use today.
1873 Batter's box introduced.
Any player, umpire, or scorer who gambles on a game he takes part in shall be expelled from his club and the National Association.

National League Rule Changes

In Chronological Order

1877 Canvas bases 15 inches square were introduced.
Home plate was placed in the angle formed by the intersection of the first and third base lines.
Player reserve clause was written into the contracts for the first time.
The base runner was out if hit by a batted ball.
The hitter was exempted from a time at bat if he walked.
1878 The number of "called balls" became 9 and all balls were either strikes, balls or fouls.
1879 Player reserve clause was for the first time put into a contract.
The pitcher had to face a batsman before pitching to him.
1880 Base on balls was reduced to 7 "called balls."
Batter no longer got a fourtth strike.
Front of pitcher's box moved to 50 feet from the center of home plate.
The catcher had to catch the pitch on the fly in order to register an out on a third strike.
1882 Pitchers now allowed to throw sidearm.
The "foul bound catch" was abolished and the pitcher could deliver a ball from above his waist.
1883 Championships were to be decided on a percentage basis.
Six "called balls" became a base on balls.
1884 All restrictions on the delivery of a pitcher were removed.
1885 A granulated substance may be applied up to 18" from the bottom of the bat.
Chest protectors worn by catchers and umpires came into use.
Home base could be made of marble or whitened rubber.
One portion of the bat could be flat (one side).
The pitcher's box was changed to 4 feet by 7 feet.
1886 Stolen bases became an official statistic.
1887 The pitcher's box was reduced to 4 feet by 5 1/2 feet.
Calling for high and low pitches was abolished.
Choice of innings given to home team captain.
Five balls became a base on balls.
Four "called strikes" were adopted for this season only.
Bases on balls were recorded as hits for this season only.
The batter was awarded first base when hit by a pitch.
Home plate was to be made of rubber only - dropping the marble type and was to be 12 inches square.
Pitcher must keep his back foot on the rear line of the pitcher's box (55.5 feet from middle of home plate).
Strike zone established between shoulders and knees.
Coaches were recognized by the rules for the first time ever.
1888 A batsman was credited with a base hit when a runner was hit by his batted ball.
Batter awarded a hit when a runner is out for being hit by batted ball.
The base on balls exemption from a time at bat was restored.
1889 A sacrifice hit was statistically recognized.
Four balls became a base on balls.
One predesignated substitute may be used at the end of any complete inning.
1890 Two substitutes may be used and may enter at any time.
1891 Substitutions were permitted at any point in the game.
Large padded mitts were allowed for catchers.
1893 The pitching box was eliminated and a rubber slab 12 inches by 4 inches was substituted.
The pitcher was required to place his rear foot against the slab.
The slab was moved from 50 feet to 60 feet 6 inches from rear of home plate.
The rule allowing a flat side to a bat was rescinded.
The requirement that the bat be round and wholly of hard wood was substituted.
1894 Foul bunts were classified as strikes.
Sacrifice hits limited to bunts and not counted as at bats.
The rule exempting a batter from a time at bat on a sacrifice was instituted.
1895 A held foul tip was classified as a strike.
Bats were permitted to be 2 3/4 inches in diameter and not to exceed 42 inches.
Infield-fly rule was adopted.
Pitching slab was enlarged to 24 inches by 6 inches.
Size of gloves limited except for catchers and first basemen.
1899 Batter awarded first on catcher's interference.
1900 Plate changed from square to five-sided figure.

Major League Baseball Rule Changes

In Chronological Order

1901 All foul balls not caught on fly counted as strikes until batter has two strikes.
Catchers were compelled to remain continuously under the bat.
1903 Height of the mound was limited to 15 inches higher than the level of the baselines.
Foul strike rule was adopted by the American League.
1908 Pitchers were prohibited from soiling a new ball.
The sacrifice fly rule was adopted.
1909 Relief pitcher must face at least one batter.
1910 Stolen base no longer credited when other runner in a double steal is thrown out.
1917 Earned-run statistics and definitions were added to the rules.
1920 All freak deliveries, including the spitball, were outlawed.
Balk to be called if pitcher releases pitch while catcher is out of his box.
The failure of a preceding runner to touch a base would not affect the status of a succeeding runner.
The batter was given credit for a home run in the last of the ninth inning if the winning run was on base when the ball was hit out of the field.
The number of runs batted in were to be included in the official score.
Frivolous ninth-inning uncontested steals in one-sided games were were to be scored as defensive indifference.
1925 The minimum home-run distance was set at 250 feet.
1926 Pitcher was allowed to use a rosin bag.
Sacrifice hit awarded when any runner advances on a fly out.
1931 Balls that bounce over the fence entitle batter to two bases.
Balls hit over the fence are to be ruled fair or foul based on where they are when they leave the field.
Sacrifice flies eliminated.
Regulations referring to a batter contacting his own ball were clarified as was the area of bases awarded a batter when a defensive player threw his glove at a batted or thrown ball or in the case of spectator interference.
1950 Home team must bat second.
Mound must be 15 inches high.
Rules for determining winning and losing pitcher established.
Size of first baseman's glove/mitt regulated.
Strike zone redefined to from armpits to top of knees.
1953 Players were to remove their gloves from the field (in 1954) when batting and no equipment was to show on the field at any time.
1954 Defensive interference was changed from an offense solely by a catcher to one by a fielder as well.
No fielder could take a position in line with a batter's vision with the deliberate intent to in any way distract the batter.
Sacrifice fly rule was brought back, this time with a man scoring after the catch only.
1959 Regulations were set up for minimum boundaries for all new parks, 325-400-325 feet.
1963 Strike zone enlarged to from top of the shoulders to the knees.
1965 The size of the catcher's mitt was regulated.
1968 The anti-spitball rule was rewritten and tightened up because of the wave of moistened pitches that floated plateward the prior season.
1969 The pitcher's mound was dropped five inches.
The strike zone was shrunken to the area from the armpits to the top of the batter's knees.
The save rule was added to the official rules for the first time.
1971 All major-league players were ordered to wear protective helmets.
1973 The rule on glove size and color was minutely outlined for standardization.
The American League began using designated hitter for pitchers on an experimental basis.
1974 The save rule was rewritten.
Minimum standards for individual championships were outlined.
1975 The ball was permitted to be covered with cowhide because of the shortage of horses.
Suspension for three days became mandatory if batter were to hit a fair ball with a filled, doctored or flat-surfaced bat.
Current save rule was adopted.
1978 Pitcher can't throw at the batter.
1988 Catchers must wear protective helmets while on defense.
2008 MLB adds limited (home run calls, fair or foul) instant replay to be in effect for all games starting on Friday, August 29th.
2014 Runner attempting to score may not deviate from his direct pathway to the plate in order to initiate contact with the catcher (or other player covering home plate). Catcher cannot block plate without possession of ball.
2016 Slides on potential double plays will require that base runners must make a bona fide attempt to reach and remain on base.
2017 Pitchers no longer required to throw four intentional balls to walk a batter. Manager may now ask the plate umpire to let the batter go to first base.
2020 Pitcher must face a minimum of three batters in an appearance or pitch to the end of a half-inning.
Temporary / COVID-19 Pandemic Rules Added for Shortened Season:
  Extra-inning runner on second base automatically.
  Seven-inning doubleheaders.
  The postseason expands to 16 teams.
  Universal designated hitter.
2022 Draft lottery implemented to discourage tanking.
The National League officialy adopts the designated hitter.
The postseason expands to 12 teams.
2023 Bases increase in size from 15 to 18 inches.
Defensive shifts are banned.
Extra-inning runner on second base, from 2020 temporary rules, made permanent.
Pitch clocks will be used.
Pitchers are allowed two disengagements per plate appearance without penalty.
Major League Baseball Rule Changes | Research by Baseball Almanac
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