The 2019 Official Baseball Rules can be viewed via the Related Link located on this page.
Below is a sampling of baseball rules changes that occured between 1880 and 1975.
- The catcher had to catch the pitch on the fly in order to register an out on a third strike.
- The pitcher could deliver a ball from above his waist.
- Six "called balls" became a base on balls.
- One portion of the bat could be flat (one side).
- Home base could be made of marble or whitened rubber.
- Chest protectors worn by catchers and umpires came into use.
- Calling for high and low pitches was abolished.
- 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.
- Coaches were recognized by the rules for the first time ever.
- Four balls became a base on balls.
- A sacrifice bunt was statistically recognized.
- Substitutions were permitted at any point in the game.
- Large padded mitts were allowed for catchers.
- Pitching distance increased from 50 feet to 60 feet 6 inches.
- 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- The rule allowing a flat side to a bat was rescinded and the requirement that the bat be round and wholly of hard wood was substituted.
- Foul bunts were classified as strikes.
- Pitching slab was enlarged to 24 inches by 6 inches.
- Bats were permitted to be 2 3/4 inches in diameter and not to exceed 42 inches.
- Infield-fly rule was adopted.
- A held foul tip was classified as a strike.
- Pitchers were prohibited from soiling a new ball.
- The sacrifice fly rule was adopted.
- The cork center was added to the official baseball.
- Earned-run statistics and definitions were added to the rules.
- All freak deliveries, including the spitball, were outlawed.
- The number of runs batted in were to be included in the official score.
- The minimum home-run distance was set at 250 feet.
- Sacrifice fly rule was brought back, this time with a man scoring after the catch only.
- 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.
- Regulations were set up for minimum boundaries for all new parks, 325-400-325 feet.
- The anti-spitball rule was rewritten and tightened up because of the wave of moistened pitches that floated plateward the prior season.
- 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.
- All major-league players were ordered to wear protective helmets.
- 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.
- The save rule was rewritten.
- 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.
- The save rule was changed again.
To read more interesting rules changes over the years, please visit Baseball-Almanac.com.