When did football players start wearing baseball caps?

1950s

This is a more difficult piece of football arcana. Actually, there are very many photographs of NFL game action from the late 1940's showing players wearing cage-type facemasks. These photos gainsay the long-circulating story that the facemask was introduced by Cleveland Browns' coach Paul Brown following an injury to Otto Graham in 1953. That claim may have been based on the fact that the Browns were actually one of the last teams to employ facemasks, and the coach's resort to the protective device was a "first" for him. It is known that helmet manufacturers designed a primitive mask in the early 1940's, but which team was the first to use masks, or which player the first to wear one is hard to pin down.