I honestly doubt Payne got pushed out. I think it's just a case of a guy who came in with the expectation that he'd be the starter with Kofi in the draft a year ago, then Kofi came back unexpectedly so he wasn't the starter. Then he was pretty terrible so he ended up playing only 7.5 minutes per game. So the whole thing just didn't work out as he intended, and he's looking for a fresh start and where he will have something closer to a guarantee in terms of playing time. Then with a coach he's been with previously being the HC at an Atlantic Sun team that is not far from home, it just seemed like the right fit.
While Underwood couldn't guarantee him a certain amount of playing time, pushing him out the door when we need frontcourt bodies just for depth makes no sense. Just having a 6'10 shotblocking presence there if you need one is nice, those are more difficult to find than one could imagine at the collegiate level.