Baseball Rules – Complete Guide
A complete overview of baseball rules, from game structure to key terms.
Game Structure
An official game has 9 innings.
Each inning has two halves:
- Top half: visiting team bats.
- Bottom half: home team bats.
An offense's turn continues until 3 outs are recorded.
If the score is tied after 9 innings, the game goes into extra innings until a winner is determined.
In Practice:
Game tied 4-4 in the 9th inning. In the top of the 10th, the visitor scores 1 run → 5-4. In the bottom of the 10th, the home team needs to score at least 1 to tie or more to win.
The Field
Diamond: four bases arranged in a square (90 feet / 27.43 m on each side).
Home plate: where the batter stands.
Pitcher's mound: 60 feet, 6 inches (18.44 m) from home plate.
Infield: the inner area of the field where the bases are.
Outfield: the grassy area beyond the infield.
Fair territory: within the lines connecting home plate to the foul poles.
Foul territory: outside these lines.
Teams and Positions
Each team has 9 players on defense:
1. Pitcher
2. Catcher
3. First baseman (1B)
4. Second baseman (2B)
5. Third baseman (3B)
6. Shortstop (SS)
7. Left fielder (LF)
8. Center fielder (CF)
9. Right fielder (RF)
On offense, the team follows the batting order from the lineup.
Pitching and The Count
Strike zone: the space over home plate between the batter's shoulders and knees.
The count:
- 4 balls → batter walks to 1st base (walk).
- 3 strikes → batter is out (strikeout).
Illegal movements by the pitcher → balk (runners advance one base).
In Practice:
Count: 3 balls and 2 strikes (full count). Next pitch: if it's a ball → walk. If it's a strike → strikeout.
Hitting
Single: batter reaches 1st base.
Double: batter reaches 2nd base.
Triple: batter reaches 3rd base.
Home run: ball leaves the park in fair territory → all runners complete the circuit.
In Practice:
Bases loaded + home run = grand slam (4 runs at once).
Runs
A player scores a run by touching all bases and returning to home plate.
Runs do not count if the third out is made before the runner touches home.
Outs
Ways to get an out:
- Strikeout → 3 strikes.
- Fly out → ball caught in the air.
- Force out → defender steps on the mandatory base before the runner.
- Tag out → runner is touched with the ball before reaching a base.
- Interference → runner or batter obstructs a defender.
In Practice:
Runners on 1st and 2nd, ball hit on the ground to the shortstop. Defense steps on 2nd base (force out) → eliminates the runner from 1st. Then throws to 1st base → eliminates the batter. Result: double play (2 outs on the same play).
Special Rules
Infield Fly Rule: a pop-up in the infield with runners on 1st and 2nd (or bases loaded) and less than 2 outs → batter is automatically out.
Dropped third strike: if the catcher fails to catch the 3rd strike, the batter can try to run to 1st base (if it's vacant or with 2 outs).
Hit by pitch: if the batter is hit by a pitch, they are awarded 1st base.
Stolen base: a runner can advance while the pitcher is delivering the pitch.
Umpires
Usually 4: home plate, 1st, 2nd, and 3rd base.
Duties: call balls/strikes, fair/foul, safe/out.
In major games, there can be 6 umpires, including in the outfield.
Plays can be reviewed by replay.
Penalties
Ejection: unsportsmanlike conduct or aggression.
Use of illegal substances on the ball: pitcher is ejected.
Delay of game: may result in a warning or penalty.
Substitutions and Strategies
Substitutions are permanent: a player who leaves cannot return.
Designated Hitter (DH): bats in place of the pitcher (current MLB rule).
Common strategies:
- Bunt: intentionally tapping the ball.
- Squeeze play: a bunt with a runner on 3rd base trying to score.
- Hit and run: runner starts running before the hit to gain an advantage.
Conduct
Players must respect the umpires.
Arguments can lead to ejection.
Fights are punished with suspensions.
Baseball Glossary
At bat (AB)
An official turn for a player at the plate.
Batting average (AVG)
The ratio of valid hits to at-bats.
Bullpen
The area where relief pitchers warm up.
Closer
A pitcher specializing in finishing games at the end.
Double
A hit that allows the batter to safely reach second base.
Double Play
A defensive play in which two offensive players are put out as a result of one continuous action.
ERA (Earned Run Average)
The average of earned runs allowed by a pitcher per nine innings.
Fielder's Choice
A play where a fielder, after fielding a ground ball, chooses to put out a preceding runner rather than the batter.
Fly Out
An out that occurs when a batter hits a ball that is caught by a fielder in the air.
Foul ball
A batted ball hit outside the fair territory.
Ground Out
An out made when a batter hits the ball on the ground and is thrown out at first base.
Ground rule double
A ball that bounces and leaves the field → batter goes directly to 2nd base.
Hit by Pitch
When a batter is struck by a pitched ball without swinging at it. The batter is awarded first base.
Home Run
A fair ball hit out of the playing field. The batter and any runners on base are awarded a run.
Line drive
A hard-hit ball in a straight line.
No-hitter
A game in which a pitcher does not allow any hits.
Perfect game
A pitcher retires 27 batters without anyone reaching base.
Pinch hitter
A player who comes in to bat in place of another.
RBI (Runs Batted In)
Runs scored as a result of a hit.
Reliever
A substitute pitcher who enters during the game.
Sacrifice Bunt/Fly
A play where a batter intentionally gets out to advance one or more runners.
Single
A hit that allows the batter to safely reach first base.
Stolen base
A successful base steal.
Strikeout
An out recorded when a batter accumulates three strikes.
Triple
A hit that allows the batter to safely reach third base.
Walk (Base on Balls)
Awarding a batter first base, after the pitcher throws four pitches outside the strike zone.
Walk-off
A play that ends the game immediately, usually a home run by the home team in extra innings or the 9th.
Practical Examples
Walk-off Home Run
Game tied 2-2 in the 10th inning, a home team batter hits a home run → final score 3-2 and the game ends immediately.
Triple Play
Bases loaded with no outs, ball hit to the third baseman, who steps on 3rd (out 1), throws to 2nd (out 2), then to 1st (out 3).
Grand Slam
A batter hits a home run with the bases loaded → 4 runs at once.