A lot of people are linking caps to all kind of sports. A sports fan will select one specifically for the team he favors. By watching closely in the sport arena you will easily find various caps are worn by the fans of different teams.
All teams will typically have two colors. Just about all teams use white. It is quite possible for any team to have three different colors of hats. They are not home and away hats. The marketing groups figure out what designs may sell and have different color hats to go with them. On top of the basic team colors, you will find special colors done for different occasions. Teams may do pink hats for the women. Or what they may do is come up with a color of a hat for a different holiday or observance.
When buying souvenirs for pro teams, you think you can be the head gear that the players wear. In some cases that is too expensive and not safe for many reasons. So to come up with something safe, you will see football baseball caps. Baseball caps are fun to wear no matter what sport they are made for.