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The rules of baseball have changed a lot even in the last 20 years, and it looks as if they will change even more over the next 20. One rule that has remained steady ever since baseball’s conception is the number of defensive players that are allowed on the field at one time.
There are nine defensive players allowed on the baseball field at one time. These players consist of a pitcher, a catcher, a first baseman, a second baseman, a third baseman, a short stop, a left fielder, a center fielder, and a right fielder.
In some leagues that allow for a designated hitter, there may be a total of ten players in the starting lineup, but there are always only nine players on defense for one team.
Continue reading the rest of this article to learn more about each defensive position.
What is a Pitcher?

Arguably the most important position on the baseball field is the pitcher.
The pitcher is the player who throws the ball to the hitter. His goal is to try and get the hitter out.
The pitcher stands on top of the pitcher’s mound and begins each play by throwing the pitch toward home plate. His role is essential to the sport of baseball as the game cannot go on without a pitcher.
Pitchers often have some of the strongest arms of anybody on the team, but arm strength is not the only ability they must possess.
In order to be successful, pitchers must also have what is known in the sport of baseball as command. Command on the pitcher’s mound can be defined as being able to throw the ball where you want it whenever you want.
On top of being able to do this, pitchers must also be able to throw a number of different pitches for a strike. Almost every pitcher throws a fastball – regardless of how fast it really is. Being able to throw offspeed pitches is also crucial for pitchers, especially at higher levels.
Some common offspeed pitches that pitchers throw are changeups, curveballs, sliders, sinkers, cutters, and sometimes splitters. Each of these pitches is often slower than the pitcher’s fastball and has a different movement in order to keep hitters off balance.
What is a Catcher?

Arguably the second most important defensive position on the baseball field behind the pitcher is the catcher.
The catcher is the player that squats behind home plate and receives the pitch from the pitcher. He wears shin guards, a chest protector, and a helmet with a facemask in order to protect his body from the dangers of the position.
The catcher’s main job is to receive the pitch from the pitcher, but his role consists of so much more than the casual fan may understand.
Catchers are also in charge of calling pitches, throwing out potential base stealers, blocking wild pitches, and keeping the pitcher in good spirits throughout the game. They are often considered to be the captain of the defense because they can see everything happen in front of them.
Catchers must have strong legs to be able to sit in the squat position over and over again throughout the game. They must also have strong arms to be able to throw out runners who attempt to steal.
Ideally, catchers are also quick enough to drop to their knees and block wild pitches and also to be able to pop up on their feet to throw to second or third base when runners attempt to steal.
These physical skills are important to being a good catcher, but just as important is the mental ability to play the position.
Catchers must be smart and tough. They must be smart because they call the pitches and also relay defensive plays in certain situations. They must be tough because squatting as much as they do can be exhausting, and blocking wild pitches in the dirt is no easy task on the body.
What is a First Baseman?

Known more for their prowess at the plate, first basemen actually play a vital role on defense.
The first baseman is one of four infield positions. The first baseman stands next to first base inside the foul lines. His job is to field batted balls that come his way and also cover first base on ground balls hit to the other infielders.
When another player in the infield catches a ground ball and throws the ball to first base for the force out, the first baseman is typically the one who covers first base to catch it.
It is important for first basemen to be apt at catching the ball, but in order to play the position successfully, one does not necessarily have to be the most fleet of foot because the first baseman is not expected to cover a lot of ground.
Most teams put one of their best power hitters at first base on defense because these hitters are often bigger and are not as quick on their feet.
With that being said, having a first baseman who is a good enough athlete to be able to stretch and catch bad throws from infielders is always a plus. While it may not be the most difficult position to play, having a great defensive first baseman is a plus for any team.
First base is also a position that left-handed throwers can play because it does not require a lot of throwing across the infield.
What is a Second Baseman?
Often viewed as one of the scrappiest players on the field is the second baseman.
The second baseman is an infielder who typically positions himself between first and second base on the right side of the infield (from the catcher’s point of view).
The second baseman is asked to cover the ground between second base and the first baseman. This usually consists of ground balls but also consists of fly balls in the infield and into shallow right field.
The second baseman is usually a quick and sure-handed defender because he must be able to cover ground but also make routine plays on ground balls.
Arm strength is not usually a priority for second basemen because the throw to first base is much shorter than other throws in the infield. Still, the second baseman has to have enough arm strength to throw the ball to first from second base on a quick double play.
Speaking of double plays, the second baseman is also charged with covering second base on double play balls hit to the left side of the infield. He also covers second on balls hit to the left side of the outfield and may cover on stolen base attempts.
What is a Third Baseman?
This next position, known as the hot corner, is not for everyone as hard-hit balls are frequent at third base.
The third baseman is an infielder who mirrors the first baseman. He often positions himself next to third base a few feet inside the foul line.
The third baseman’s duties include fielding ground balls hit in his direction as well as covering third base on stolen base attempts and balls hit to the outfield. He is also often charged with fielding bunts that are directed toward the third base line.
The third baseman is typically a sure-handed defender with a strong arm. What he may gain in arm strength, he may lack in speed and foot quickness. Still, he must be quick enough with his hands to field hard-hit line drives and ground balls hit in his direction.
Third basemen are typically bigger and stronger versions of shortstops but more athletic versions of first basemen. Having a quality defender at third base bolsters a defense. When the third baseman is not a strong defender, offenses often take advantage of him in bunt situations.
What is a Shortstop?
Even non baseball fans often know what a shortstop is. What they don’t typically understand is where exactly the shortstop plays on the field and what his responsibilities are.
The shortstop is one of four infielders. He positions himself between second and third base, mirroring the second baseman. He is often described as the captain of the infield.
The shortstop’s job is simple: try to catch everything. Whether it is a ground ball or fly ball, the shortstop’s responsibility is to try to get to everything he possibly can.
While it is unrealistic to believe that he will actually get to everything, most shortstops are the best athletes in the infield, so putting this task on him ensures that most batted balls go into the hands of your best player.
Shortstops often combine the abilities of all of the infielders. They should be able to cover a lot of ground, they should be sure-handed, and they should have strong arms. This is a lot to ask of someone at one position, so it is no wonder as to why they are usually the best athletes.
The shortstop is also tasked with covering second base on double plays to the right side, balls hit to the right side of the outfield, and sometimes on stolen base attempts. He is also the cutoff man for balls hit over the outfielders’ heads to the left side.
What is a Left Fielder?

It is time to learn about the last line of defense on the baseball field: the outfield. On the left side of that defense is the left fielder.
The left fielder is one of three outfielders who plays on the left side of the outfield (from the catcher’s point of view).
He is charged with catching fly balls on the left side of the outfield and fielding ground balls that are hit his way and getting them back into the infield as quickly as possible.
There is often confusion among beginners in the sport about where left field is actually located, but here is a good rule of thumb. Left and right on the baseball field are always established from the catcher’s point of view. Therefore, left field is located on the third base side.
The left fielder does not necessarily have too many defining traits. Of course, he must be apt at catching fly balls and must be fast enough to cover some ground.
While arm strength is a plus in left field, the left fielder normally has the weakest arm of all of the outfielders because he is tasked with making the shortest throws.
What is a Center Fielder?
If you have ever been to a professional or minor league baseball game, you have likely heard the lyrics, “Put me in coach. I’m ready to play today. Look at me. I can be centerfield.” John Fogerty’s song, “Centerfield”, sums up why it is one of the most important positions on the field.
The center fielder is one of three outfielders who plays right in the center of the outfield (hence the name) between the left and right fielder.
Like the shortstop, the center fielder’s job is to try and catch everything. In fact, the center fielder has priority over everyone on the field when it comes to catching fly balls. If he calls to catch it, everyone else must get out of the way.
Center fielders are often the fastest players in the outfield because they are tasked with covering the most ground on the field. They have all of the ground in front, behind, and in each gap to cover.
This is a lot to ask of one player. However, most of them are up for the challenge because most center fielders are aggressive by nature. Many of them also have good arm strength, but some coaches are willing to sacrifice arm strength for speed at this position.
What is a Right Fielder?
At younger levels of baseball, the right fielder is normally viewed as the weakest link on the team. However, at higher levels of the game, having a quality right fielder is vital to having a quality outfield.
The right fielder is the third of the three outfielders who lines up on the right side of the outfield. He mirrors the left fielder.
The right fielder has the same duties as the left fielder; he just plays on the opposite side of the field. The biggest difference between the left and right fielder is usually their arm strength.
Right fielders are sometimes tasked with throwing the ball from right field all the way to third base. When trying to decide between whether two outfielders should play left or right field, it is usually a good rule of thumb to put the player with the stronger arm in right field.
What is a Designated Hitter (DH)?
While there are always only nine players on defense at one time, ten players can actually be in the starting lineup on a baseball all thanks to the designated hitter.
The designated hitter, usually known as the DH, is a player who hits in the batting lineup in place of another player who only plays defense. The DH does not play defense.
It is called the designated hitter because this player is designated to hit for a player each time that spot in the lineup comes up to bat. The DH is typically a player who is a strong hitter with some weaknesses on defense.
In Major League Baseball, the DH almost always hits for the pitcher. In lower levels of baseball, like high school for example, the DH does not just hit for the pitcher.
He can hit for any player in the lineup. This is often used for the player who is strong on defense but may be a liability on offense.
In Major League Baseball, only American League teams were allowed to utilize the DH while pitchers for National League teams were required to hit. However, in 2020 the MLB enacted the universal DH meaning that teams in both leagues could opt to use a designated hitter.
What is an Extra Hitter?
Similar to the designated hitter, sometimes an extra hitter is allowed at lower levels of baseball.
The extra hitter is a hitter who hits in the batting lineup but does not play defense. Unlike the designated hitter, he does not hit in place of another player in the lineup.
The extra hitter is usually only allowed in amateur leagues in order to get more players more at-bats.
Related Questions
Can a team play with fewer than nine players?
It is possible to play with fewer than nine players on defense in some amateur leagues. However, most leagues require teams to start with nine players. If injuries require them to finish with fewer than nine, it depends on the league’s rules as to whether or not the team can play.
How many players are on an MLB roster?
Major League Baseball rosters allow for 26 players to be listed as active members of the team. Each team is also allowed a 40-man roster. The extra 14 players are relegated to the minor leagues but may be called up to the MLB team at any time.