Baseball Rules

The Rules of Baseball

Baseball's origins are not entirely clear. The sport may have been influenced by similar, British games such as rounders and cricket. It is believed that baseball was first played in America during the 1700's. While some say that Civil War general Abner Doubleday invented the sport, this information is debated.

Baseball is a sport that is played on a field, between two opposing teams. The biggest and most popular professional baseball organization is Major League Baseball (MLB), which has twenty-nine teams in the United States and one team in Canada. There are two leagues within Major League Baseball, consisting of fifteen teams each: the National League and the American League. Each year, around late October or early November, the World Series takes place. The World Series is MLB's championship series. The two remaining teams from the MLB postseason play a best-out-of-seven series to determine the championship team. Other notable accomplishments in the MLB are being inducted into the National Baseball Hall of Fame, playing in the All-Star Game (an annual game each July played by the MLB's biggest stars), and winning various awards such as a Golden Glove (for defensive players) and a Silver Slugger (for hitters).

In 2019, some of the top players include outfielder Mike Trout of the Anaheim Angels, outfielder Mookie Betts of the Boston Red Sox, and third/second baseman Jose Ramirez of the Cleveland Indians. Some of the MLB's best pitchers include Max Scherzer of the Washington Nationals, Chris Sale of the Boston Red Sox, and Jacob deGrom of the New York Mets.

The Field

A baseball field is a large, almost always outdoor field that consists of grass, dirt, bases, and white lines that denote the different boundaries. It is sometimes called a baseball diamond because it is shaped like a diamond.

Baseball field

There are two main parts to the field: the infield and the outfield. The infield consists mostly of dirt, and it is home to the bases and the pitcher's mound. The bases are evenly-spaced marker points arranged in a diamond, and they are respectively called first base, second base, third base, and home plate.

Home plate is a pentagon-shaped platform that is located at one corner of the infield and baseball diamond. The rest of the bases are square-shaped. The bases and home plate are usually made of rubber.

Starting from home plate, the bases are ordered in a counter-clockwise sequence. First base is located to the right of home plate, on the right corner of the infield. Second base is located directly across from home plate, on the top corner of the infield. Third base is located to the left of home plate, on the left corner of the infield. On a Major League Baseball field, the distance between the bases is 90 feet.

Located at the center of the bases is the pitcher's mound. The pitcher's mound is a small hill of dirt, at the center of which is a rectangular slab of rubber called the pitcher's plate. A member of the defensive team, called the pitcher, stands at the pitcher's plate. You will learn more about pitchers later in the article. On a Major League Baseball field, the pitcher's plate is located 60.5 feet away from home plate.

The other part of the field is called the outfield; it is on the opposite side of the infield from home plate and almost exclusively consists of grass. The left one-third of the outfield is called left field. The right one-third of the outfield is called right field. The one-third in between the two is called center field. These reference points (left and right) are from the perspective when looking at the outfield from home plate.

The main lines on the field illustrate the boundaries of play, and they border half of the diamond, extending from either side of home plate all the way to the end of the outfield. (The other half of the diamond is framed by the fence bordering the far side of the outfield, called the outfield fence/wall.) These lines are called foul lines. At each of the two points where the foul lines meet the outfield wall, there is a large yellow pole. These poles are called foul poles. You will learn more about fouls later in the article. On a Major League Baseball field, the minimum distance between home plate and the center field fence is 400 feet. The minimum distance between home plate and either foul pole is 325 feet. However, most MLB fields exceed these dimensions, at least for the outfield (the distances between the bases, home plate and the pitcher's plate, etc. are standard league-wide).

The Objectives

The objective of baseball is to score a higher number of runs (a tallying unit also called "points" in other sports) than the opposing team in order to win the game.

One team plays offense, which means their objective is to score runs by hitting the baseball from home plate, which allows them to advance through the bases, and hopefully ultimately end up back at home plate. If the runner makes it all the way through the bases back to home plate, the team scores a run.

The other team plays defense, which means their objective is to get the offensive players "out" so they do not score runs. When an offensive player gets out, they must exit the playing field, and sit back on the bench. When three outs are obtained, that marks the end of the half-inning, and the two teams switch: the team that was previously playing defense now plays offense, and the team that was previously playing offense now plays defense. You will learn more about half-innings later in this piece.

One way an offensive team can advance bases and ultimately score runs is by hitting the baseball. This happens when a member of the offensive team, called the batter, stands at home plate. He holds a bat, which is a long, thin club made of wood or aluminum. He faces the pitcher's mound, where a member of the defensive team called the pitcher is standing with the baseball.

The pitcher uses a special throwing technique to throw the ball toward the batter. This act of throwing is called pitching; the throw itself is called the pitch. If the batter thinks he is able to hit the pitch, he swings his bat and tries to make contact with it. Other defensive players are stationed in different parts of the baseball field, and their objective is to prevent the ball from touching the ground. If they catch the ball, the batter is automatically out. If the ball touches the ground, the batter has the opportunity to run to first base. Meanwhile, the defensive players are working as fast as they can to pick up the ball and throw it to the defensive player stationed at the base the batter (whose label now changes to "runner") is approaching. If the defensive player at the base obtains the ball and steps on the base before the runner reaches it, the runner is out. If the runner touches the base before the defensive player at the base has the ball, the runner is safe.

baseball pitcher

However, the batter does not always make contact with the ball. Stationed behind home plate is the catcher, a defensive player whose primary job is to catch the pitches the batter does not make contact with. If the batter swings and misses (does not make contact with the ball), the batter gets one strike.

Strikes are like a punishment for the batter and a reward for the pitcher, because if three strikes are obtained, the batter is out. Another way to obtain a strike is when a batter does not swing at a pitch, but the pitch is inside the strike zone. The strike zone is an imaginary box above home plate that extends from the batter's chest to his knees. It is considered a reasonable area in which a batter is realistically able to hit a ball. If a pitch is outside the strike zone and the batter does not swing, he gets one "ball." Balls are like the inverse of strikes: a reward for the batter and a punishment for the pitcher (for throwing a pitch outside a reasonable range). If four balls are obtained, the batter gets a walk, which means he automatically gets to reach first base.

Moving The Ball

As mentioned earlier, part of the objective of the defensive players is to either catch the ball, or, if the batter hit the ball and it touches the ground, the defensive players attempt to pick it up and throw it to the base the batter (now called the "runner") is approaching. The defensive players who are stationed at the bases and in the outfield are known as fielders. They use specially designed gloves/mitts made of leather, which provide padding in the palm of their hands and in between their fingers to allow them to easily pick up and catch the baseball. Once a fielder has successfully picked up a ball, he throws it to the fielder most suitable in getting the batter out (this is usually the fielder stationed at the base the runner is approaching). Sometimes, if the ball has travelled especially far into the outfield, the fielder who picked it up will it to another fielder who is relatively nearby (but positioned closer to the bases). That second fielder will then throw it to the appropriate fielder at the bases.

Game Format and Duration

MLB games consist of nine innings. Each inning consists of two half-innings. A half-inning begins with one team on defense and the other on offense; once three outs are obtained, the half-inning ends. The teams then switch roles - the team that was on offense now plays defense, and vice versa - and the next half-inning begins fresh with zero outs. Unlike other sports such as basketball and football, baseball does not run on a timed clock - instead, innings are the unit of organizing game length.

The first half-inning of each inning starts with the visiting team on offense and the home team on defense. The first half-inning is called the "top of the inning" and the second half-inning is called the "bottom of the inning".

In MLB games, the length of time between innings ranges from 2 minutes and 5 seconds to 2 minutes and 55 seconds (depending on broadcast type and whether it is a postseason game).

Games do not end in ties in professional baseball. If the score is tied by the end of the ninth inning, the teams keep playing for as many extra innings as it takes for a team to have a greater number of runs than the other. Remember - each team gets a try at playing offense and defense during each full inning, so even if a team scores a run at the top of an inning, that lead must be maintained to the end of the bottom of that inning.

baseball inning

Teams and Players

In the MLB, each team has an active roster of 25 players. An active roster means that that set of players is always ready and available to be pulled off the bench and put in to play on the field. Teams also have 40-man rosters, and these consist of players who are part of the team but not necessarily immediately available to play (such as injured players or players in affiliated Minor League teams).

Each baseball player specializes in one or a few defensive positions. There are nine defensive positions: pitcher, catcher, first baseman, second baseman, third baseman, shortstop, left fielder, center fielder, and right fielder. The different positions correspond to where each player stands on the field. The only 2 positions whose names don't correspond to an area of the field are the catcher, who squats behind home plate, and the shortstop, who is stationed between second base and third base.

The nine defensive players are also the ones who take turns batting at home plate when it is their team's turn to play offense. That's why, for many ballplayers, it is crucial to have prowess at a certain defensive position while also having strength in batting.

baseball positions


As mentioned earlier, a baseball bat is a stick-like club made of wood or aluminum. It is thinner on the end that is meant for a batter to hold, called the handle. The other end of the bat, called the barrel, is significantly thicker, and it is the part of the bat that makes contact with the ball. The part of the bat that is in between, where the handle gradually thickens into the barrel, is called the throat.

As also stated before, a baseball glove is a leather glove/mitt specially designed to assist defensive players in catching and picking up the ball.

The baseball itself is made of string that is very tightly wound around a rubber or cork core. It has an outside skin consisting of two thin strips of leather stitched together. A baseball is roughly 9 inches in circumference.

baseball equipment list

Fouls and Penalties

A foul ball occurs when a batter hits a baseball, and it lands outside of the foul lines, not in between them. Remember that the foul lines border the field from home plate all the way to the outfield fence. If the ball lands in between or directly on the foul lines, it is within the field of play, and is called a fair ball. If it lands beyond the outfield fence, it is something called a home run (batter and any runners on base automatically make it back to home plate and score one run each), and is not a foul. But if it lands to the left of the left foul line, to the right of the right foul line, or behind home plate, it is considered a foul ball.

Foul poles mark the point where the foul lines meet the outfield fence. If a ball lands outside the foul poles, it is a foul ball. If it touches one of the foul poles, it is a home run (since the foul poles are simultaneously part of fair territory and the outfield fence).

baseball foul ball

If a batter has zero or one strike and hits a foul ball, it counts as one strike. If the batter has two strikes and hits a foul ball, it does not count as a strike. He will still have two strikes regardless of the number of foul balls he hits. However, regardless of how many strikes there are, if a defensive player catches a ball that is outside the foul lines before it touches the ground, the batter is automatically out.

Scoring and Winning

An offensive team scores runs when its runners advance the bases and make it back to home plate, all without getting out. One way an offensive team can advance bases and ultimately score runs is by hitting the baseball and not getting out. Another way is by getting "walked" (remember that a walk is given if the pitcher throws four balls). Another way is by hitting a home run. A home run is a ball that is hit so far, it lands beyond the outfield fence. As mentioned earlier, the batter and any runners on base automatically advance through the bases and make it to home plate, with each batter/runner scoring one run for the team.

baseball run

How a team scores runs might look something like this: A batter hits the ball, it lands on the ground, and as fielders are trying to pick up the ball, it gives the batter enough time to run to first base and stay there before the fielders are able to throw the ball to get him out. The next batter might draw a walk; he then occupies first base and allows the previous batter (now called a "runner" because he reached base) to go to second base, since two offensive players cannot occupy the same base at the same time. Then the next batter might hit a home run, and he and the two players on base will all get to finish the sequence of bases and end up back at home plate. In this sequence, the offensive team will score 3 runs: 1 for the batter who hit the home run, and 2 for the 2 players who were occupying a base when the home run was hit.

Summary of Baseball Rules

  • A professional baseball game lasts nine innings.
  • Each inning consists of two half-innings, which further consist of three outs being made.
  • If the score is tied at the end of the ninth inning, the teams immediately play extra innings. They play as many extra innings as is necessary for a team to score more runs than the other.
  • A defensive team has nine players on the field: one at each designated position.
  • An offensive team can have anywhere from one to four players on the field: a batter at home plate, and one to three runners on the bases.
  • An MLB team has a 25-player active roster, consisting of players who can readily be put on the field.
  • An MLB team also has a 40-player roster, which consists of the 25 active players as well as some injured or Minor League players.
  • If a batter hits a foul ball, it will only count as a strike if he currently has zero or one strike. If the batter already has two strikes, the foul ball will not count as a strike.
  • If a defensive player catches a hit before it touches the ground, whether the ball is inside or outside the foul lines, the batter is out.
  • The bases are spaced 90 feet apart and are arranged in a diamond formation.
  • A baseball measures between 9 and 9.25 inches in circumference.