On February 27, 1912, the New York Yankees announced they would begin wearing pinstripes on their uniforms (notably, this was two years before Babe Ruth even made his Major League debut, thus debunking the myth that Yankee pinstripes were worn in an attempt to make him appear slimmer). According to an article in the New York Times:
When manager Harry Wolverton’s Yankees trot out from their clubhouse on April 11 to open the season with Boston, Hilltop fans will see their favorites togged out in uniforms closely resembling those worn by the Giants last season. The fad for the pin stripe in baseball toggery, introduced by the Cubs a few years ago, has reached the Hilltop, and the home uniforms of the Yankees this year will be of that design. The home uniform will consists of white shirt and pants, with black pin stripe and “N.Y.” on the left breast; a white cap with a blue monogram, and blue stockings with maroon stripes.
The Yankees opted to abandon the pinstripe look, however, following the 1912 season. They brought them back in 1915 in navy blue, rather than black.