CinemaBlend’s Laura Hurley had suggested that the One Chicago franchise should send Foster over to Chicago Med, which seems like a smart move if that would work out schedule-wise.
Keeping Foster in the conversation on Chicago Fire, even sporadically, could help make that transition eventually occur, and it would make sense for the franchise to keep her within the fabric of the show for that reason.
It sounds as though Chicago Fire will indeed keep viewers updated on how things are going with Foster, who will no doubt be struggling to get through medical school.