The Yankees, as an organization, are trendsetters. The first AL club to add pinstripes in 1915 (they briefly wore them in 1912), the Yanks also became the originator of making digits permanent on the back of jerseys in 1929. Cleveland used numbers on the left sleeve of the home jerseys in 1916.
While the Yanks still hold their no facial hair policy in high regard (except for a neatly trimmed mustache that doesn’t extend past the corner of the lips), and have yet to introduce a third jersey, to be worn during the regular season, the Yankees have evolved with the times.