Many rules changed during the span of Baseball. Instead of explaining your answer, I'll give you some extra information on all of the things that have changed since 1877.
1877
- 15 inch square canvas bases were introduced.
- Home plate was placed in the angle formed by the intersection of the first and third base lines.
- The hitter was not counted an At-Bat if he was walked.
1879
- Umpires were introduced.
- All balls became "strikes," "balls," or "fouls." and the number of "called balls" was a ridiculous 9.
- The Player Reserve Clause was put into a contract.
- The pitcher had to stand facing a batter before pitching to him.
1880
- A walk was lowered to 8 "called balls"
- If the batted ball hit a runner, he was now declared out.
- On the third strike, the catcher was required to catch the pitch on the fly in order for an out to register.
1883
- The "foul bound catch" was abolished and the pitcher could deliver a ball from above his waist.
1884
- All of the restrictions on the deliver of a pitcher was removed.
- Base on balls is now reduced to 6 "called balls."
- Championships were to be decided on a percentage basis.
1885
- One side of the bat was allowed to be flat.
- home base could be made of marble or whitened rubber.
- Catchers and Umpires began using chest protectors.
1887
- The pitcher''s box was reduced to 4 feet by 5 1/2 feet
- Calling for high and low pitches was abolished.
- Base on balls reduced to 5 balls.
- This is the only year 4 "called strikes" was adopted.
- Base on balls were recorded as hits for this year only.
- The batter could now walk to 1st base if hit by the pitch.
- Marble was no longer allowed to be Home Plate, and the dimensions were changed to 12 inches.
- The rules recognized coaches for the first time.
1888
- Player reserve clause was written into the contracts of minor leaguers.
- Base on balls, again, did not count as an At-Bat.
- Batsman was awarded a base hit if he hit a runner with a batted ball.
1889
- Base on Balls again reduced to 4.
- The statistics of a sacrifice bunt were recognized.
1891
- Substitutions were permitted at any point in the game.
- Large padded mitts were allowed for catchers.
1893
- Pitching distance increased from 50 feet to 60 feet 6 inches.
- The pitching box was eliminated and a rubber slab 12 x 4 inches was substituted.
- The pitcher was required to place his rear foot against the slab.
- A sacrifice bat did not count as an At-Bat
- A flat sided bat was no longer allowed. The bat now had to be fully round and made completely of hard wood.
1894
- All foul bunts were counted as strikes
1895
- Pitching slab was enlarged to 24 x 6 inches.
- Bats were permitted to be 2 3/4 inches in diameter and not to exceed 42 inches.
- The Infield-Fly rule began.
- A foul-tip held by the catcher became a strike.
1901
- Catchers were compelled to remain continuously under the bat
1903
- Foul strike rule was adopted by the American League.
1904
- The height of the mound was limited to 15 inches higher than the level of the baselines.
1908
- Pitchers were prohibited from soiling a new ball
- Shin guards were reintroduced.
- The sacrifice rule was adopted.
1910
- The cork center was added to the official baseball.
1917
- Earned-Run statistics and definitions were added to the rules.
1920
- All freak deliveries, including the spitball, were outlawed.
- 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 discarded.
1925
- Pitcher was allowed to use a resin bag.
- The minimum home-run distance was set at 250 feet.
1931
- The Sacrifice-Fly rule was brought back, only if a runner scored after the catch.
- Defensive interference was changed from an offense by the catcher only to all fielders.
- No fielder could take a position in line with a batter's vision with the deliberate intent to distract the batter in any way.
- 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.
1953
- The rule was added (for 1954) that no equipment was to be shown on the field while batting. They had normally left their gloves on the field.
1959
- All new parks had to have minimum boundaries of 325-400-325 feet.
1968
- The anti-spitball rule was rewritten more strictly because of the number of wet pitches.
1969
- The pitcher's mound was lowered to 10 inches.
- The strike zone became smaller, from the armpits to the top of the knees.
- A pitching save was added to the official rules.
1971
- Helmets became mandatory for all batters.
1973
- The rules for glove size and color was standardized.
- The Designated Hitter was experimented by the American League.
1974
- The Save rule was rewritten.
- Minimum standards for individual championships were outlined.
1975
- Horse shortage allowed balls to be covered with cowhide.
- 3-Day Suspension was mandatory for any batter caught using a filled, doctored, or flat-surface bat.
- The Save rule was rewritten again.
2008
- Limited Instant Replay is added to the rules starting Friday, August 29 for Home Run calls and Fair or Foul calls.
