Tampa gets a slightly younger, NHL proven option at C that will save them a ton of money (I expect McMichael to sign an ~2x2.5 bridge deal). Obviously, Cirelli is the better player next year and has a higher ceiling, but given the incredibly strange reacquisition of McDonough it seems like something has to give to bring back Stamkos or address the poor depth on the roster.

Caps could also take back some other questionable salary such as Sheary to facilitate the deal.

Caps get the bona-fide top 6 guy they are looking for who's locked up on a fair contract for all of his prime.