User blog comment:Pseudobread/Bioshock Infinte DLC features new AI companion?/@comment-5290577-20130712015821/@comment-189.142.208.133-20130712170743

Except Ken said the DLC would be playable from the start, without having to finish the game. Playing the DLC would be confusing for people who haven't finished the game. Furthermore, I remember reading somewhere that the DLC won't expand the main campaign in any way, and the Booker Vox Martyr story would do that in some way.

My money is on it being a standalone DLC, like Minerva's Den from Bioshock 2.