William Gay, a 30-year-old corner for the Pittsburgh Steelers, was fined $5,787 on Wednesday for violating the NFL's uniform rules.
According to ESPN, Gay was fined for wearing these purple cleats, which do not match the Steelers back and yellow uniforms.
Gay wore purple for Domestic Violence Awareness Month, for which he is a vocal advocate. Gay has been personally affected by domestic violence: His mother was killed by his stepfather when he was 7.
His agent and representative, Jerrold Colton, confirmed the NFL's fine via Twitter.
The NFL does have long-standing guidelines regarding uniforms, regulations that are set before the season begins.
The rules for shoes reads as follows, "League-approved tri-colored shoes are permitted with black, white, and one team color."