Baseball Rules Reference

The baseball rules that directly affect how the scorecard renders. If you're new to baseball, start with How to Read a Scorecard first.

The basics

A baseball game has two teams. They take turns batting (offense) and fielding (defense). Each turn is called a half-inning. The visiting team bats in the top half, the home team bats in the bottom half. A standard game is 9 innings, but extra innings are played if the score is tied.

Each half-inning ends when the fielding team records 3 outs. An out can happen by:

• Striking out (3 strikes)
• Catching a fly ball
• Tagging a runner or base before the runner arrives
• Various other situations (interference, infield fly rule, etc.)

Batting order

Each team sets a lineup of 9 batters before the game. They bat in order, cycling back to the top after the 9th batter. The batting order cannot change during the game, but a substitute can replace a player in their spot.

On the scorecard, each row represents one lineup slot (1-9). Multiple players may appear in the same slot if substitutions were made.

Strikes, balls, and the count

Each at-bat is a duel between the pitcher and batter:

• Strike: the batter swings and misses, doesn't swing at a pitch in the strike zone, or fouls the ball off
• Ball: the pitch is outside the strike zone and the batter doesn't swing
• 3 strikes = strikeout (batter is out)
• 4 balls = walk (batter takes first base)
• Foul balls count as strikes, but a foul ball cannot be the third strike (except on a bunt)

Hits and reaching base

Event	What happens
Single	Batter hits the ball and reaches first base safely
Double	Batter reaches second base on a hit
Triple	Batter reaches third base on a hit
Home Run	Ball goes over the outfield fence (or batter circles all bases on a hit inside the park)
Walk (BB)	4 balls, batter takes first base
Hit by pitch (HBP)	Pitch hits the batter, takes first base
Error	Fielder makes a mistake, batter reaches base
Fielder's choice	Batter reaches because the fielder chose to retire a different runner

Double plays

A double play records two outs on one play. Most common: runner on first, batter hits a ground ball, fielder throws to second base (runner out), relay to first base (batter out). This is called a 6-4-3 double play.

On the scorecard, each out appears in its own cell. The batter's out in the batter's cell, the runner's out in the runner's cell.

Sacrifice plays

Sometimes a batter intentionally makes an out to advance a runner:

• Sacrifice bunt (SH): batter bunts to advance the runner, knowing they'll be thrown out at first
• Sacrifice fly (SF): batter hits a fly ball that's caught, but a runner on third scores by tagging up

Stolen bases and caught stealing

Runners can attempt to advance to the next base while the pitcher is delivering a pitch:

• Stolen base (SB): runner advances successfully
• Caught stealing (CS): runner is thrown out attempting to steal

Pitching changes

Managers can replace their pitcher at any time. The departing pitcher's stats (strikes, pitches, strikeouts) are shown on the scorecard at the point of substitution.

The infield fly rule

When there are runners on first and second (or bases loaded) with fewer than 2 outs, and the batter hits a pop fly that an infielder could catch with ordinary effort, the batter is automatically out, even if the fielder drops the ball. This prevents fielders from intentionally dropping the ball to get a double play. Marked as (IFF) on the scorecard.