It is already figured out by Fallout fans that Fallout 4 is going to be set in Boston. This is evident in Fallout 4’s trailer, which showed the NPCs in the game wearing baseball apparels.
Baseball is really a popular sport in Boston and this became a major subject of discussion from the fans. The Fallout lovers are now expecting baseball outfits to become exclusive armours in Fallout 4.
Just like how the Legion utilized football outfit to become armours in previous Fallout games, the fans felt that it is only right if baseball outfit receives the same treatment.
Hence, Fallout lovers can look forward to a new faction being introduced in Fallout 4 and they will all be equipped with baseball uniforms. A confirmation on this is bound to happen at E3 when Fallout 4 gets officially unveiled.