Who says he wants to even leave? Playing regular football at 20... Moves to us and becomes a squad player. Would he not be better signing new deal, getting another 1 or 2 seasons at current club then they can sell for £25m rather than £10m and he gets 2 more years full time playing rather than bit part - the opposite of sterling.
If he doesn't then that's his loss cos sticking round the munchers will only end up limiting the scope of his career.
If he's got any ego and confidence and drive he will move.

