He sold Mata to United when they were a direct rival for the title. He also sold us Rom. If we make the best offer, and Mata wants to join, I see no reason to think Jose wouldn't sell him to us.
Doesn't seem like there are any credible links (outside of esk) when it comes to Mata coming or going. But if Mourinho was willing to sell him once, you'd think he would be willing to do so again. The fact we aren't seeing him linked with other big clubs gives me optimism that he'll still sign...
Sure would be encouraging to see a few credible links saying we're close to signing Mata. Pretty rare for players of his caliber to just sign with a club seemingly out of the blue.