Did You Know? The first time a Major League baseball team wore numbers was on June 26, 1916. Inspired by football’s and hockey’s use of numbers, the Cleveland Indians trotted on their home field wearing large numbers on their left sleeves. This “experiment” was tried for a few weeks, again the next season, and then abandoned. Then In 1929, the New York Yankees were planning to start the season with uniform numbers on the back of the jersey. The Indians also planned to wear numbers in this fashion. The Yankees were rained out on opening day, April 16, while the Indians played, making Cleveland the first MLB franchise to wear numbers on the back.