He'll go abroad. Heinze wanted to go to Liverpool and the club said no, and no matter how much he spat his dummy out we held firm and he had to go to Real. I can see the same happening again. We might end up making less than if we were to sell him to City or Chelsea, but we wont be strengthening a rival no matter what.
I can imaging him going to PSG. He'll be one of the big names there, in a league that isnt as strong as the English league so he wont even need to be at the level we expect of him every week, which will hide when he isnt at his best (which has been the case for a while).
It suits PSG as well, Rooney is a big name and would be a statement of intent for them as a club that they want to be a force to be reckoned with in Europe. City would only want him to say they have got one over on us again, Chelsea I cant imagine wanting to spend another £50 million on a striker that has had form issues, and I can't see Pep wanting a player like him either (talented, but some attitude issues - some similarities to Ronaldinho at the end of his time at Barca). Real Madrid would depend on who their manager is, I wont rule them out totally. But PSG just seems to fit