Baseball Roster Rules

baseball roster rules

Baseball is a game played in a ballpark with two teams of nine players on the field at one time, each under the leadership of a manager. One or more umpires are charged with interpreting the rules dictating game play. The team with the greater number of runs at the end of the game is the winner.

While baseball is only played with nine players on the field for each team, a full baseball team includes many more players and coaches. Many members of a baseball team function as backups, and teams will often have multiple players in any one position. Read on to learn all about rosters in Major League Baseball!

What is a Full Roster in Baseball?

baseball team roster

Baseball is a game played between two teams. The teams are rather large, each consisting of 40-man rosters. However, on game day, the team size is shortened to a 26-man roster in Major League Baseball. The defensive positions on a team include a pitcher, a catcher, three basemen (first baseman, second baseman, and third baseman), a shortstop, and three outfielders (centerfielder, leftfielder, right fielder). These same players are also responsible for being batters when their team is on offense.

So how many players are on a baseball team? In Major League Baseball, each team has two types of rosters: a 26-man active roster and a 40-man expanded roster. The 26-man roster consists of players who are specifically playing major league games, while the expanded roster includes players drafted by the team who are currently in the minor leagues.

26-Man Active Roster

The 26-man active roster includes the players who are in the dugout, in uniform, ready to play at any moment during the game. Only players who are part of the 40-man roster are allowed to be a member of the 26-man active roster. The remaining members of the 40-man roster are placed on their team’s minor league affiliate, and do not attend or play in major league games unless they are called up by the team. Additionally, players who are injured and placed on the Injured List (IL) are not counted towards a team’s 26-player total.


27th Man

In the event of a doubleheader (two games played between the same two teams on the same day), Major League Baseball allows teams to include a 27th player on their active roster. However, this player must also be on the 40-man roster and a team’s active roster can only reside at 27 active players for the day of the doubleheader. In the event the 27th man is demoted back to the minor leagues after the day of the doubleheader, they must remain in the minor leagues for at least 10 days before they can be promoted back to the big league ball club again. This rule is in effect until the start of September, when September call-ups are permitted.

28-Man Active Roster

Late in the MLB season, the league allows teams an “expanded roster” that will permit teams two additional players, bringing their total roster size to 28 players. These two additional players must also be a part of the 40-man roster, and are known as “September call-ups.” This is done in the interest of making sure teams have ample pitchers/hitters to rest their starters when necessary in the back end of the MLB season. The end of the season is known for being particularly brutal to players, as athletes are over 100 games into the season and the wear and tear their body takes starts to add up. Once the league has initiated the year’s expanded roster period, team’s are allowed to call up a 29th player for the day of a doubleheader with the same rules the 27th man has during the earlier portion of the season.


40-Man Roster

The 40-man roster includes everyone on the 26-man roster, as well as all the players signed to a Major League contract with the team. These players can be called up to join the 26-man active roster, but are not available right away to play in the game. Typically, these players will play for the minor league team that is affiliated with the major league city. Additionally, unlike other rosters listed above, players on the 10 or 15-day IL still take up spots on the 40-man roster. Only players who are on the 60-day IL will not count towards a team’s 40-player limit. The 40-man roster is also crucial in that players who are not on their team’s 40-man roster and meet service time qualifications may be eligible to be taken by other teams in the Rule 5 Draft.

Rule 5 Draft

Outside of eligibility to be promoted to the major league ballclub, the Rule 5 Draft stands as the main thing teams factor in when deciding who to place on their 40-man roster. The Rule 5 Draft occurs each December, and during the draft teams are allowed to take players from other team’s rosters so long as they are not on the 40-man roster and meet certain service time qualifications. Qualifications for a player to be taken in the Rule 5 Draft are as follows:

  • Drafted/signed at 18 or younger with five seasons of service time
  • Drafted/signed at 19 or older with four seasons of service time

While you may assume the players taken in the Rule 5 Draft must not be of major consequence, seeing as teams have ample opportunity to protect them, this is not the case. Top players to change teams in the MLB Rule 5 Draft include Josh Hamilton (2010 AL MVP and 5x All-Star), Jose Bautista (6x All-Star and 2x MLB home run leader), and Bobby Bonilla (6x All-Star). Each of these MLB superstars were taken in the Rule 5 Draft before they broke out to become star players for the teams fortunate enough to take advantage of another team’s oversight.


Postseason Roster

Like the regular-season roster, the postseason roster consists of 26 players. However, in contrast to the regular-season, there are specific rules for rosters during the postseason. Typically, any player on the roster of a baseball team is eligible to play in the postseason, even if they are on the expanded 40-man roster or the Injured List. Players on the Restricted List are also eligible, so long as they have not been suspended for the use of performance-enhancing drugs. Players who do not meet any of the above criteria can still be added to the postseason roster by making a petition to the Commissioner’s Office. However, in order to do so, the player must have been with the league since August 31st of the season, be replacing a player on the IL, and have served the minimum time required for activation (for example, 10 days on the 10-day IL and 60 on the 60-day IL).

A new roster is submitted for each round of the playoffs, and can contain either the same players or different players. Players can be replaced if they are injured during a playoff series, but they then become ineligible for the rest of that round and the entirety of the next round, if there is another round following the series. According to the rules, pitchers can only be replaced by other pitchers, and likewise for position players.

New MLB Roster Rules

In 2022, the MLB introduced new rules regarding the size of team rosters for the start of the season. From April 7th, 2022 (Opening Day) to May 1st, 2022, the usual 26-man roster will be increased to a 28-man roster. Teams will be able to add a 29th player for doubleheader games or games resumed on the same day as another scheduled game. These expanded roster rules are the same as the September call-up rules for the latter portion of the season.

In addition, restrictions on the number of rostered pitchers (usually 13 maximum) or position players appearing as pitchers will not apply during the April 7th through May 1st period. Players are eligible for placement on the 10-day IL prior to this May 1st date. However, on May 2nd, they must be placed on the 15-day IL. These rules were added in the interest of player safety and to help adjust to the condensed 2022 schedule.


Minor League Options and Waivers

Minor league options and waiver are important transactions teams can use to manage their active and 40-man rosters.

Minor League Options

Minor league options are used to send players down to the minor leagues, removing them from the 26-man roster. When a player is optioned to the minor leagues, they remain on the 40-man roster, but not on the 26-man roster. However, players only have a certain number of “option years” in which teams can do this. Players are assigned three options when they are first promoted to the Major Leagues; however, they can lose an option each year depending on how their team utilizes them. Specifically, if an optioned player remains in the minor leagues for more than 20 consecutive days, they will officially have one of their minor league options taken away. Players can only lose one option per year. Once a player has run out of minor league options, they must be designated for assignment in order to be sent down to the minors. This also means they are removed from the 40-man roster and passed through waivers.



Waivers are how Major League Baseball teams demote players who no longer have options attached to them. The difference between waivers and options is that when a player is waived, every other team in the league has the option to “claim” them so long as they add the claimed player to their active roster. Teams are given the right to claim the waived player in the order of their current record, with the worst team’s getting the first shot at them. Teams in the player’s league (American or National) also have priority over the other side of the league.

This system is meant to give players who have been waiting years for their opportunity in the big leagues a chance to shine with a new team that actually has use for them on the big league roster. MLB teams do have one “rescission option” on players they waive each year, which allows them to retain the player and place them back on their active roster. However, once this option has been used on a player once, it can’t be used again. Players that pass through waivers successfully can be sent to the minors, traded, or released at the team’s discretion.

Lastly, but also worth mentioning, players who have accumulated three or more years of service time, or who are waived outright to the minor leagues at any point in their career, are able to reject demotion to the minors and elect to become a free agent instead.


Baseball Manager

There are two types of managers in baseball: the manager (also called the “field manager”) and the general manager:



When people talk about the manager in baseball, they usually are referring to the on-field coach who is the main leader of the team. The manager is also occasionally called the “field manager,” in order to distinguish him from the general manager, who heads the team as an administrator for the overall organization. He is also often referred to as the “skipper.” In comparison to other sports, the manager’s position is essentially similar to the head coach of a football team, while the general manager is analogous to an NFL team owner.

Usually, the manager sits in the dugout during a game and watches the action unfold with the players, making important strategic decisions about the game, including batting order/lineup, which player will fill each defensive position, pitching order/rotation, and in-game player substitutions. The manager will act as a coach, and will also typically address reporters and the press at conferences directly before and after the game, discussing strategies and how the team played. The manager also issues instant replay challenges, supervises practices and spring training, and keeps control of their players in the event of a controversial call.

The vast majority of MLB managers are former baseball players. This is because former ball players tend to have an intimate understanding of the game, and can insert themselves into their players shoes. Managers often have a deep understanding of how a clubhouse works, but they will also know how to interact and work with the front office, upper management, and the general manager.

General Managers

The general manager works more on the administrative side of a baseball team. He oversees the building of the roster, including things such as scouting and recruitment efforts, contract negotiation, roster construction, and budget management. He is also in charge of employing and making changes to the coaching staff, and does some interacting with the media, like the manager. Some baseball teams will have a head position known as the President of Baseball Operations, and in these cases, the general manager will generally serve as the second-in-command under the President. 

The general manager is an extremely important component to the team, as his decisions affect the makeup and chemistry of the entire team. A team's long-term success relies on the prowess of its general manager. To that end, general managers often employ many assistants and department heads in their running of a franchise. Famous MLB general managers in history include Theo Epstein of the Boston Red Sox and Chicago Cubs, Ed Barrow of the New York Yankees, and Ken Williams of the Chicago White Sox. 


Retired Numbers

Each baseball player wears a number on his jersey which, among other players on the roster, is unique only to him. Sometimes, when a player is exceptionally great, usually in a combination of skill, personality, and historical impact, their number is retired by the team. This means that their number cannot be worn by any current or future player of the team, so the number will always belong to that player. It is a special way for teams to honor their brightest stars.

Only one player's number is retired by every team in Major League Baseball: number 42, Jackie Robinson's number. Jackie Robinson was the first African-American player in the MLB. Every year, on April 15, the anniversary of Robinson's first Major League game, every player in the MLB wears 42 in honor and memory of him.


How many players are there on a baseball team?

The number of players on a baseball team can vary during various points in the year, featuring either 26, 27, 28, or 29 players depending on the point in the season. For almost the entirety of the season MLB rosters feature 26 players on the active roster, except for doubleheaders where teams feature a total of 27 players. In September, MLB teams expand to feature 28 players and 29 total on days in which they have a doubleheader.

When did the MLB get rid of the 25-Man roster?

The MLB Rules required baseball teams to have 25-man active rosters for 101 years, between 1919 and 2020. This rule, however, was changed at the start of the 2020 season, allowing teams to have a 26-man active roster, with the option of adding two more players (for a total of 28) after September 1st. Teams are also allowed to add a 27th man to their rosters in the event of a doubleheader.

When do MLB teams have to finalize their rosters?

MLB teams must have their official 26-man rosters finalized prior to Opening Day, which is typically sometime in late March or early April. However, changes to the roster can be made during the season, such as calling up players from the 40-man roster or demoting players to the minor leagues. In the postseason, 26-man rosters must be submitted and finalized before each successive playoff round. 

How many players are on the field at once in baseball?

Excluding batters and potential baserunners, there are nine players on the field at any given time. These nine players are the pitcher, catcher, first baseman, second baseman, third baseman, shortstop, left fielder, center fielder, and right fielder. Factoring in batters and baserunners, the most players there could possibly be on the field at once is 13. This would occur if the bases were loaded.