Pittsburgh Bureau of Police officers providing security for the Pittsburgh Pirates game responded when a fan accessed the field at about 3:40 p.m.
It was the top of the sixth inning when a male casually walked onto the field towards home plate. He appeared to extend his hand toward the players for a handshake.
Officers quickly intervened, escorting the male off the field where he was arrested and handcuffed in front of the Philadelphia Phillies dugout.
The male told police he did it because a friend dared him to.
The 24-year-old, who is from Central Pennsylvania, faces charges of trespassing and disorderly conduct.