It's a tough question.
Normally I'd say no, but with the crazy money that some people are quoting, why not?
That being said, however crazy City are, I don't think they'd spend that much on JT. Regardless of whether or not they did, we'd not only be losing one of our best and influential players, we'd also be losing our captain. You also have to take into account the man's friendship with Frank Lampard, I'm not saying Frank plays well because of JT (far from it, that'd be outrageous) but to be able to play on the pitch week in-week out with a guy and make such a friendship (which we're led to believe they have), it'd surely knock him a bit.
I'm not so sure that the benefits of selling him outweigh the negative points. However much money we get for him, it'd affect the team as a whole, he's our captain and there are no big influences in our team, not even Lampard could fill his role as a permanent captain, he's just not as big a character.
We say we need the money, really we don't. Roman's goal is self-sufficiency, if we made anywhere near £50m (which just wouldn't happen), how much of that would go towards a new defender, or a new captain, or just a new player in another position? Not much I bet. We were £60m off break-even point this season, despite the fact that half of it was due to managers, that's still £30m off, even if we improve on that, we wouldn't be spending a big amount of money as there's still quite a bit of a way to go to break-even.