"Street Clothes"

As big of a sports fan as I am, I can't help but notice that often, when a player is injured but shows up to a game to cheer his team on (particularly in basketball), the television broadcast will cut to a shot of the player sitting on the bench, and the broadcaster will say that he is "in street clothes" because of whatever injury. What I want to take issue here is the term "street clothes". These guys are usually wearing nice, custom suits - in fact, I think there might be a league-mandated dress code. In any case, that's not the kind of stuff most people actually wear on the street. Now, maybe professional athletes dress nicer than the average person, but I still don't think that they'd be wearing that kind of thing when they're out with their posses.