I don't think it's completely implausible. Phoenix wants to trade Gortat. He's got a decent contract, but this means they are limited in the amount of salary they can take back (also, the Phoenix owner is a cheapskate.) Melo's D-league play has not hurt his stock, and Bass's contract isn't atrocious. I think they'd prefer Bradley, but if Bradley were available Gortat would already be a Celtic.
We'd probably have to add some sort of draft compensation unless Bass remembers how to play basketball in the next two weeks, but I don't think such a deal is implausible. Unlikely, yes, because all deals posted on Celticsblog are unlikely, but I've seen (and probably proposed) worse.
That said, I don't do this deal, because I'm I'm favor of blowing it all up, and trading for Gortat doesn't fit that plan too well.