The Basic Rules of Baseball

A game of baseball is played by two teams of nine players. Each team tries to win the game by scoring the most runs (points). The players on each team play both offense and defense—the teams switch from offense to defense after every three outs, as explained below.

Baseball Defense Basics

The goal of the defensive team is to prevent the offensive team from scoring runs. The defensive teams does this by getting outs. There are two ways to get outs:

Pitching: The pitcher’s job is to pitch (throw) the ball to batters and try to get them to strike out. A pitch is considered a strike when a batter swings at the ball and misses, or when a batter doesn’t swing at a pitch but it is ruled a strike by the umpire. (see Pitching in Baseball)
Fielding: If the batter hits a pitch, the defensive players, also called fielders, try to get an out by catching the ball on the fly or fielding (picking up) a ground ball and throwing it to a base ahead of the batter or other baserunners.

Baseball Offense Basics

The two main parts of offense in baseball are hitting and baserunning.

Hitting (batting): When a team is on offense, it sends players one by one up to home plate to bat. The batter’s goal is to get on base, either by drawing four balls (pitches that aren’t strikes) or by getting a hit. A hit is a ball that is neither caught in the air nor fielded and thrown to first base ahead of the batter.
Baserunning: If the batter hits the ball into fair territory, the batter becomes a runner—he drops the bat and runs toward first base. If the player reaches first base safely without getting out, the player is considered safe and stays at the base. If the runner thinks he can make it to second or third base without getting out, he runs past first and continues to the farthest base he thinks he can make it to safely.

After the batter either gets on base or gets out, the next batter comes to the plate and repeats the process, attempting to get on base safely and help advance the other baserunners to home plate, where they score a run. When a runner circles all four bases and touches home plate without getting out, the team at bat is awarded one run. The offense sends batters up to the plate until the defense gets three outs, at which point the two teams switch places—the offensive team plays defense, and the defensive team gets a chance to bat.

Innings

Every baseball game is divided into nine units of play called innings. In each inning, both teams take turns batting and playing the field. Each inning is divided into two halves known as the top and bottom. During the top of an inning, the home team plays in the field, and the visiting team bats. After the home team gets three outs, the game moves to the bottom of the inning, and the teams switch places.

If a game is tied at the end of the ninth inning, the teams play extra innings until one team has more runs when a complete inning ends (after the third out at the bottom of an inning).

Officiating the Game

Major League games are officiated by a team of four umpires, often called umps for short, each of whom occupies a specific part of the field:

First base
Second base
Third base
Behind the plate

An umpire’s job includes ruling whether runners are safe or out at a base and whether a ball is hit in fair or foul territory. The umpire stationed behind the plate is responsible for calling whether a pitch is a strike or a ball. In addition to making judgment calls regarding the game’s play, umpires also maintain order on the field. When they feel that a player or coach is being unsportsmanlike, such as arguing strenuously against an ump’s ruling, the umps may eject the player or coach from the game.

Player Substitutions

Though a baseball team has only nine active players in the game at all times, a team has a total of 25 total players on its roster. Those 25 players usually consist of:

8 starting fielders: The fielders who play in the field at the beginning of the game
5 starting pitchers: The pitchers who start games and try to pitch at least 5–6 innings of the game (teams usually have 4–5 starting pitchers, who make up the team’s pitching rotation)
6–7 relief pitchers: Pitchers who come into the game if the starting pitcher runs into trouble or tires
5–6 bench players: Fielders or hitters who can be substituted into the game for other players to provide offensive or defensive help

During the course of most games, the manager, or head coach, of the team replaces some fielders or pitchers with bench players or relievers (relief pitchers). A player substituted out of the game cannot return to the game.

Offensive Substitutions

Pinch hitter: A pinch hitter is a player brought in off the bench to bat in place of the player due to bat. Pinch hitters are often brought in late in the game to hit for a pitcher or other weak hitter.
Pinch runner: If a slow runner reaches base when a team desperately needs a run, the manager might sub in a faster pinch runner to take his place.

Fielding Substitutions

If a batter or runner is removed from a game, he must also be replaced in the field. The pinch hitter or runner can take over the removed player’s fielding duties, or the manager can bring in another player to play the field. Occasionally, in trying to preserve a lead, a manager may make a purely defensive substitution, replacing a poor fielding player with a better fielding player from the bench.

Relief Pitchers

When the pitcher in the game is tiring, isn’t pitching well, or was subbed out for a pinch hitter, the manager replaces him with a relief pitcher. Managers must plan these replacements carefully, since relievers need to throw in the bullpen (warmup area) before playing. Often a manager calls a time out and makes a trip to the mound to discuss the current pitcher’s stamina, give him a pep talk, instruct him on how to pitch to a particular batter, or just give the reliever more time to warm up. If the manager visits the same pitcher on the mound twice in the same inning, he is required to remove that pitcher from the game.

When deciding which relief pitcher to bring in, the manager considers which batters are due up in the opposing team’s lineup and how his relief pitchers have fared against those batters in prior games. In making his decision, he also likely factors in that left-handed batters tend to struggle against left-handed pitchers, whereas right-handed batters tend to have trouble with right-handed pitchers.

Acknowledgments & Disclaimer