Don't let him go, make him turn up every week, warm up like the rest of the squad and then sit him on his arse for the duration. He signed a contract, he has an obligation he freely accepted, just like the bags of money that came from your pockets - hard earned not to be made fools of - and if you let this mega ego take the piss, well the next one will know what to do.
Not as if you'll sell him anywhere decent really, it's MLS time for Ronnie, last few pay days before he gets to sit in TV studios telling fans what rubbish they are watching - in his day, blah blah.
Humiliate him, he's no true servant of anyone but himself.