In Fallout 4, you're working your way through Boston, home of the 8-time World Series Champions of baseball, the Red Sox. Heck, Fallout 4 has a post-apocalypse version of their home field, Fenway Park, built right into the wasteland. Now with a new mod, you can dress in the Red Sox uniforms. Batter up.
The mod comes from Richie Branson at Nexus mods and features several different uniforms of the Red Sox line-up, including classic star #9 Ted Williams and current player #34 David Ortiz. The threads look pretty authentically close to the real Red Sox uniforms. Featured below, you can see a video of the uniforms on an active player in the Fallout 4 world.
It's pretty interesting, considering that there doesn't seem to be any confirmation of actual in-game uniforms of this sort despite Fenway Park being in the game, but it's the next best thing to Bethesda actually getting cleared to post some "Pre-War" baseball memorabilia in DLC. If that point ever comes though, you can probably expect mods like this will get weeded out pretty quickly.
Till then, you can find the details and download links for the mod