What is a Bullpen in Baseball? (Definition, Purpose & More)

A. Coatess

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A. Coatess



Sean Hunter

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what is a bullpen in baseball

Baseball teams must prepare to utilize their physical abilities along with their strategic planning. And only the teams with the best strategies are known to win the game.

To be strategic, everyone must know all the nitty-gritty details of the game. Here, let us talk about an important part of the game: what is a bullpen in baseball?

Bullpens refer to the area in the outfield where relief pitchers prepare before stepping into the game. It can also be used to call a group of relief pitchers.

Let us dive deeper into this baseball topic!

Bullpen in Baseball: The Definition


In baseball, the bullpen definition can refer to two things:

  • The area where pitchers warm up and mentally prepare before stepping into the game. That aside, relief pitchers also stay and wait here before they get called to play.

Bullpens are usually placed behind the first or third baseline. Sometimes, it is behind the outfield wall. However, in high school or college games, the bullpen might be seen on the foul territory adjacent to the first or third baselines.

In a game, each team has different bullpens. Each pen has plates and pitching rubbers, which are perfect for players who are warming up and doing some bullpen pitching.

  • The term bullpen is also used to refer to the baseball team’s relief pitchers. You may also see people refer to them as “pen,” which is a common bullpen synonym.

The History and Evolution of Bullpens


All MLB stadiums have bullpens ready for both teams playing. But you may be wondering – why is it called a bullpen in the first place?

Going back to what is written in history, there are not much-known reasons why the word bullpen came along. A common theory among the community is that the bullpens on the field look a lot like rodeo pens where bulls are reserved.

But what we do know is the bullpen baseball origin. Back in the 1900s, pitchers used to warm up outside the field. The area where pitchers warm-up back then was just made of wooden benches for doing simple stretching exercises.

As years went by, the baseball community understood the significance of the bullpen in strategizing games. Part of the molding of the modern bullpen is the increasingly competitive nature of the sport and the fact that relief pitchers are called to play more often.

Purpose and Role of the Bullpen for Baseball Teams


  • The main role of the MLB bullpen is to give a nice place for pitchers to warm up. These pitchers primarily train their pitches to make sure that when it is their time to play, they will give it their best shot!

The two rubbers and plates on the bullpen are separated at a dimension of 60 feet and 6 inches, the standard measurement set by the MLB. Thanks to this, pitchers would have an accurate feel of their practice throws.

  • The relief pitchers are very different from the starting pitchers, who are tasked to pitch during the first innings. They are the most skilled among the team’s pitchers.

Meanwhile, the bullpen relievers are players responsible for replacing the starting pitchers when they could not continue the game. The relief pitchers are known for their versatility to bring wins to their teams.

Different Types of Relievers


Aside from the bullpen baseball meaning, let us also talk about the different types of relievers in the game.

The relief pitchers are tasked to pitch after the team withdraws their starting pitcher due to strategic reasons. They are further classified under the following types:

  • The long reliever is usually called to pitch at least three innings, or the starting pitcher needs to be pulled out of the game unexpectedly.
  • The middle reliever delivers a pitch or two during games.
  • The setup man enters at around the seventh inning to help their team retain their lead or at least come to a tie with the opponent.
  • The closer is a reliever that enters the ninth inning when they have lead runs.
  • Lastly, there is a left-handed relief pitcher that is called to play when the opponent is a left-handed batter.

Frequently Asked Questions

When do bullpen pitchers play?

Relief pitchers waiting in the bullpen are called to play depending on the team’s strategy. Common reasons they are called in are due to poor performance or injury of the starting pitcher.

Furthermore, the relief pitchers are called to close the game to secure their winning pitch.

How many players are in the bullpen?

In the MLB, teams are allowed to have a maximum of 13 pitchers. Here, the teams may have seven to eight relief pitchers ready in the bullpen.


Now, you have learned another important part of baseball strategy. This article answered the question of what is a bullpen in baseball.

This area for warm-up of relief pitchers is important to prepare them physically and mentally before they are called to deliver a winning throw for their team. The term can also refer to the group of pitchers!

During the early years of baseball, the bullpens are not given as much importance as it is today. But luckily, many teams now know how important it is to the players.

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