The St. Louis Cardinals were the first National League team to assign uniform numbers, experimenting with numbers on their left sleeves in 1923 and 1924. Eight seasons later, in late June or early July of 1932, they placed numbers on their backs, a practice adopted by all teams by the end of that season.

Uniform numbers are helpful when authenticating game-used bats. When written on the knob, a uniform number can help you date a bat or determine if someone used it other than the player whose name is on the barrel.

On this site, you can research which players wore a particular number; you can look up players by their last names to see which number(s) they wore; or you can search by season.