It's a way to help identifiy the player. In the old days of Baseball, names weren't used on the backs of uniforms, and the only way you were able to identify most players were by numbers and scorecards. Numbers tend to be chosen by the players themselves or assigned by the teams if they have no preference. Teams started wearing numbers in the 1920's to help the people in the stands tell who was who. (I've read that the Sporting News was against it because they thought people would stop buying scorecards.) Nowadays numbers have no intrinsic meaning, but originally they just used 1-9 in lineup order. So, for example, Babe Ruth was #3 and Lou Gehrig was #4 because Ruth batted third and Gehrig batted fourth. They didn't stick to that idea very long, tough.
a number
That is the uniform number of Harmon Killebrew.
nominal
Number 3 on the Philadelphia Athletics.
CC Sabathia on the Yankees
He played every position, but Bugs Bunny didn't have a uniform number in the classic 1946 Warner Bros. animated short "Baseball Bugs."
Tom Tresh Uniform Number 15Tom Tresh wore uniform number 15 for the New York Yankees from 1961 -1969.
This is a one or two digit positive integer.
what did GI origunally stand for on the uniform of American military
32
the baseball uniform is white or gray. The top is the Jersey.
They did not use uniform numbers when Honus Wagner played baseball.