Why would that have to place it post-Avengers? It’s not like Agent Hill was recruited during the movie. She’s already well-established as part of the organization in the opening scenes.
As an aside, are they going to actually get Samuel L. Jackson for a TV show, or are they re-casting Fury, or are they just going to write around a lack of him?
I’ve read that Jackson is contractually required to play Nick Fury as part of his agreement for his likeness in the comics. I imagine that Fury won’t be part of the series.
SHIELD isn’t exactly a small organization. It doesn’t take much ‘writing around’ to not have to use him, any more than it would require ‘writing around’ the absence of Robert Mueller if the show was about the FBI.