Over his 14 seasons as the dean of AL umpires, Sheridan became the prototype of the 20th century umpire. Whereas umpires in the 19th century had worked behind the plate in a standing position, believing that it helped them to better observe the flight of the ball, Sheridan established the practice of crouching while calling balls and strikes, a move which was quickly adopted universally due to its effectiveness. He was also remarkable in that he refused to use any sort of protection other than a mask. He was agile enough to reportedly never be hit by a foul ball.