Just thinking here, if Danny moved Pierce to a team with cap space (who'd buy him out) +3M and a minimal return that would give the C's a large trade exception and room under the apron. Could that then be used in a S&T to acquire a free agent?
You could in theory then pursue Tyreke Evans, Al Jefferson et al via S&T.
It seems like if you are going to release him you might as well find some team looking to get rid of a 5-6M contract and take that on so the $ are even and create a trade exception of ~10M.