How Does MLB Assign Umpires? Crews, Rotation and Postseason Picks

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MLB assigns umpires through its umpiring department, which groups the roughly 76 full time umpires into crews of four and schedules each crew for series throughout the season. Assignments are balanced so crews see every team without working the same clubs too often, and within each series the umpires rotate positions daily so each one works home plate about every fourth game. Postseason spots are earned through performance evaluations. The chart below walks through the full process.

How MLB assigns umpires
From the schedule to home plate in 9 steps
How umpires are grouped, scheduled, rotated and picked for the postseason.
1
Umpire operationsMLB’s umpiring department, run out of the league office, builds every umpire assignment for the season.
WHO DECIDES
2
Crews of fourThe roughly 76 full time umpires are grouped into about 19 crews of four, each led by a veteran crew chief.
STRUCTURE
3
Season scheduleCrews are assigned to series, usually three or four games, and travel together from city to city.
SCHEDULE
4
Balance and fairnessAssignments spread each crew across both leagues and all divisions so no crew sees the same teams too often.
RULE
5
Travel limitsMLB tries to limit cross country trips and back to back time zone jumps for crews.
RULE
6
Daily rotationWithin a series, umpires rotate positions each game, so each one works the plate about once every four games.
ROTATION
7
Replay center dutyUmpires take turns working in the replay operations center in New York, reviewing challenges for every game.
ROTATION
8
Vacation and fill insEach umpire gets scheduled vacation during the season; Triple A umpires on the call up list fill the open spots.
STAFFING
9
Postseason selectionPlayoff assignments are earned through performance evaluations, with the top rated umpires getting the World Series.
POSTSEASON
Staff size and crew counts change slightly each year with retirements and promotions from Triple A.

How the Daily Rotation Works

Crews rotate clockwise around the field. The umpire who worked first base moves to home plate the next day, the plate umpire moves to third, and so on.

Game Umpire A Umpire B Umpire C Umpire D
Game 1 Plate First base Second base Third base
Game 2 Third base Plate First base Second base
Game 3 Second base Third base Plate First base
Game 4 First base Second base Third base Plate

How Postseason Umpires Are Chosen

Round Umpire crew
Wild Card Series Six umpires, adding umpires in left and right field; crew chiefs do not work the plate in this round
Division Series Six umpires chosen from the top performance evaluations
League Championship Series Six umpires, typically veterans with strong ratings
World Series Seven umpires rotating through six spots, so in a full series each works the plate once and sits out once

Postseason crews are assembled from individual umpires rather than regular season crews, based on season long grading of ball and strike accuracy, rules knowledge and game management.

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MLB announces every postseason crew, like its 2025 World Series umpire assignments, on MLB.com.