Juan Mata doesn't appear to be one of Jose Mourinho's favorite players and might spend quite a few games on the bench for Chelsea this season, but that doesn't mean that he's for sale, and it definitely doesn't mean that he's for sale to Tottenham Hotspur.
Gianluca Di Marzio says that Spurs' reported interest was for real and that they made a bid, but Chelsea rejected it.
I'm not sure what kind of bid a Sky Six Premier League team would have to make for Chelsea to consider parting with Mata. Chelsea aren't exactly hard up for money, so it would be a lot more than Mata's actually worth to any of those teams.
It's probably safe to assume that this bid was made before Spurs started aggressively pursuing Christian Eriksen. The Dane isn't as good as Mata, but for a fee that's €21.5 million cheaper, I'm not crying over missing out on Mata. We took a punt on something unlikely and it didn't work out. Oh well.