Despite Mourinho's assertion in The Express last month that Mata is not for sale, and the man himself indicating that he is still happy at Stamford Bridge in an interview with The Mirror, rumours persist that he wants to leave.
The fear that he could miss out on a place in the Spanish squad for the World Cup if he continues to sit on the bench is certainly real, and there are plenty of clubs across Europe who would like to acquire his services.
Click through for the latest news on Mata's transfer status.
---LAST UPDATED THURSDAY DECEMBER 4---
Tony Banks of the Daily Express believes that Mata's performance against Southampton will have made Mourinho fall in love with him all over again. Whilst it might not turn out to be quite so straightforward, it seems like Mata will be getting a good run of games in the run-up to Christmas, which would effectively remove his only reason for leaving Chelsea.
Chelsea fans backlash against Rafa Benitez last November was entirely predictable. Nobody would have expected that exactly 12 months later there would be a small section of the fanbase rebelling against Jose Mourinho.
Blues Supporters around the world have taken to Twitter to question the Special One's judgement over Mata's place in the squad.
Some have been quite polite.
Others less so.
Mourinho's post-match comments on Tuesday certainly hinted that he would be rotating the squad more frequently as the fixtures begin to pile up. What that means for Mata remains to be seen, but it is clear that the warmth of the Special One's return will be forgotten by January if Chelsea's Player of the Year is allowed to leave.
French sporting daily le10sport are reporting that an agreement has been reached between Mata and the board at PSG for a deal to be done in January. According to their source, Jose Mourinho is the only thing standing between Mata and a £40 million move to the French capital.
There is one thing that is obvious, which is I can't change the rules and I can't start the match with 12, 13 or 14. I'd love that because many people deserve to play and Juan is one who deserves to play because of the way he works, behaves, the way we see him every day. But if I play him and I don't play (Eden) Hazard or Oscar, you are asking me about Hazard or Oscar in this moment. It's a consequence of the squad we have where, for these three positions behind the striker, we have so many options. It's hard for me. I don't have a special pleasure leaving players out. I enjoy playing them and making them happy, but there's nothing I can do.
This certainly indicated that Mata's exile will likely continue.
However in his post-match press conference, Mourinho indicated that he would need the full strength of his squad during the hectic Christmas period. Dominic Fifield of The Guardian had this quote from a disappointed Blues manager.
It's not the kind of game where I'm very upset with the players because I think I get it: I understood. Maybe I should have made more changes from Saturday, but when the team's played so well, you want to give them more confidence, you want them to keep that going. But I could see many signs of fatigue. I'd spoken with all of the players individually before I made the team decision, and all of them had told me they were perfect to play. They wanted to play. They'd recovered well from the international week and Saturday, but the reality is they weren't. In positions where I had other solutions, probably I should have changed the team. Today is a day when I'm disappointed, not upset with the players.
Paris Saint-Germain inquired about the availability of Juan Mata on transfer deadline day in the summer, with The Metro reporting that a £40 million offer was made for the player.
While that interest was dismissed by Chelsea, Laurent Blanc is hopeful of success with a fresh offer in January, according to the Daily Star's Nick Lustig.