Villas-Boas signed the Spain international when he was in charge at Stamford Bridge but Mata has struggled to convince current boss Jose Mourinho he is worth a starting berth.
Spurs face Chelsea at White Hart Lane on Saturday and after playing the whole of their 2-0 Capital One Cup win over Swindon in midweek, Mata has admitted he is hoping to feature more regularly.
But Villas-Boas was quick to deny speculation he may make a bid for the player and instead backed him to rediscover his form in west London.
"It's not my decision to pick or not pick Mata, it was before," he said.
"He was always involved in my starting XI, I have always enjoyed a great personal and professional relationship with Juan Mata but it's not my decision anymore.
"I suppose the time that he's not being given now, with the talent that he has he will overcome it and jump back into the team because he is that player, that special."
But when asked if he was interested in signing Mata, Vilas-Boas simply said: "No, I don't think so."
The Portuguese also spoke about how he felt after being sacked by Chelsea in 2012 and looked ahead to this weekend's meeting with his former employers.
"The emptiness is not related to Chelsea, it's completely related to the game and the adrenalin the game gives you," he added.
"The emptiness is more related to the fact you come away from your job, a 24-hour relationship with your profession and with football that gives you so much adrenalin and motivation.
"So after that Chelsea experience it was a time for me to reflect and with my staff to try to sort things that we have done wrong and to do it better in the future.
"It's important for everybody I think we are enjoying our ride at the moment, the start of the season has been excellent.
"It would be good to build on this, particularly in such an important game. Arsenal have a difficult game at Swansea and we'd like to keep ourselves in the top."
Villas-Boas also had some positive team news, with Aaron Lennon closing on a return to action after a foot injury.
"He is due to come back hopefully tomorrow (Friday) to training. He is making great progress and we should see him back to first team training next week.
"The rest, (Nacer) Chadli has come back very strong so he's in with a chance, Younes is not yet 100% so is in doubt. Danny Rose is a 90% possibility that he will play."