There are rules prohibiting logos and messages on helmets, the uniform, uniform undergarments, footwear, and even sideline towels. These rules dictate that nothing is allowed to appear without explicit approval from the league office.
Then there are Articles 7 and 8 in the rulebook, which read more like blanket provisions designed to stem players attempting to use games as a promotional platform.
As Article 7 explicitly states, “Throughout the period on game-day that a player is visible to the stadium and television audience (including in pregame warm-ups, in the bench area, and during postgame interviews in the locker room or on the field), players are prohibited from wearing, displaying, or orally promoting equipment, apparel, or other items that carry commercial names or logos/identifications of companies, unless such commercial identification has been approved in advance by the League office.”
Article 8 is a similarly worded provision that prevents players from “wearing, displaying, or otherwise conveying personal messages either in writing or illustration” unless – wait for it – the league approves them.
Some forms of personal messages are strictly prohibited altogether, including “political activities or causes, other non-football events, causes or campaigns, or charitable causes or campaigns.”