In most major league ballparks, the bullpens are located out of play just behind the outfield fences. In some ballparks both bullpens are adjacent to each other while in others the bullpens are separated with each team's bullpen located on the side of the field corresponding with the same team's
dugout. Often the outfield walls in front of the bullpen contains see-through areas to allow the bullpen to be more easily seen by both fans and the manager in the dugout, as well as to allow the players in the bullpen to more easily see what is occurring on the field. For a time, many fields had their bullpens on the field of play, usually in foul territory, down the line from each team's dugout. This location has fallen out of favor as the bullpen mounds are considered a tripping hazard for fielders attempting to catch foul fly balls and the lack of enclosure leaves players exposed to being hit by line drive fouls or stray practice pitches. As of the 2026 season, only
Tropicana Field bullpens are located in foul territory.
Wrigley Field featured an unusual orientation to its bullpen. During a
major renovation in 2017, the bullpens were moved from foul territory to underneath the outfield bleachers, making it the first and only enclosed bullpen in a major league park. ==Bullpen cars==