Original: Early developments The New York Knickerbockers were the first baseball team to use uniforms, taking the field on April 4, 1849 in pants made of blue wool, white flannel shirts and straw hats.
Simplified: Their uniforms were pants made of blue wool, white flannel shirts and straw hats. Creation On April 4, 1849, the New York Knickerbockers became the first team to use uniforms.