The NFL's deal with Reebok is as a uniform and garment manufacturer. In exchange, eebok get sto proclaim itself as the official uniform supplier to the NFL. Jerseys, pants, socks, compression shirts, girdles, etc are manufactured by Reebok. Players are allowed to wear whatever shoes they choose (although wearing a non-League approved brand will generate a fine). Reebok signed it's licensing deal in 2001 or 2002. Prior to that, each NFL team had it's own deals with suppliers for game uniforms with companies such as Wilson (IMHO, the very best), Nike, Reebok, Starter, Russel Athletic, Puma, and Reebok. The NBA did something similar around 2002.
On an aside, Riddell is the official equipment supplier to the NFL. Riddell gets to plaster its logo everywhere in NFL stadiums in exchange for giving Power shoulder pads (the very best. The new Power Extreme pads are the best you can buy, period) and Riddell helmets. But like teh equipment deal, players can wear other brands of shoulder pads and helmets. A majority of Green Bay Packers, dallas Cowboys, and New england Patriots players wear Douglas pads (excellent pads). Other players wear Impact brand shoulder pads (new but very expensive). Players also wear other manufacturer's helmets such as Schutt and Adams. One way to immediately identify a non-Riddell branded helmet is to look at the nose bumper on the front of the helmet. If it is a Riddell helmet, it will almost always say "Riddell". If it is a Schutt or Adams helmet, it will either have a blank bumper or it will say the team name (i.e. Tony Romo wears a Schutt Air Advantage helmet. The nose bumpe on his helmet is unmarked).
Just a bit of trivia.
