Public address announcer

The public address announcer is the person who announces starting lineups, relief pitchers, pinch-hitters and other items of note during a baseball game. This was originally done through a hand-held megaphone, but was eventually replaced by a microphone connected to loudspeakers.

The first major league ballpark to have a built-in public address system was the Polo Grounds, with the system first being used on July 5, 1929.