Originally Posted by Dark Raven
It can if there's a framing device around them so that someone is retelling events and it expands upon them. Or even without someone retelling, it could still say "6 months earlier" etc. They do that with lots of shows. Heroes had episodes set in the past occasionally. Even Arrow shows Oliver Queen's time on the island every week even though that happened 5 years ago before the present day in which it is set.
I guess I don't see much reason to reuse the footage from those scenes, though. Perhaps I'm failing to see the narrative value of those scenes in terms of how they could frame a SHIELD episode well. I also don't know if the Whedons would even want to incorporate scenes that are wholly foreign to their own show/writing.