An MLB game is officiated by 4 umpires: 1 home plate umpire and 3 base umpires (1st, 2nd, 3rd).

The home plate umpire calls balls/strikes and oversees plays at home plate, including obstruction calls.

Base umpires determine whether runners are safe or out on force plays, tag plays, and stolen base attempts.

The Crew Chief, the most senior umpire, leads the team and handles disputes with managers.

MLB’s Instant Replay system, operated from New York, uses multi-angle video to review and overturn close calls.

Umpires begin their careers in the Minor Leagues and advance to MLB through performance evaluations.

Umpire schools (e.g., Wendelstedt School) offer 5-week programs focusing on rules, mechanics, and fitness.

Call-Up Umpires from Triple-A leagues temporarily replace MLB umpires during injuries or rest days.

Mastery of the MLB Official Rules, including annual updates (e.g., pitch clock rules).

Strike zone calls must be made within 0.4 seconds, with an error margin under 1 inch (2.54 cm).

Physical endurance: Standing for 3-4 hours per game and daily agility drills.

Mental resilience is critical to remain calm during confrontations with players/coaches.

Proficiency with replay technology: Confirming rulings via headset with New York within 30 seconds.

MLB’s umpiring system blends tradition with technology, requiring precision, fitness, and unshakable composure.