Fernando Torres has arrived in Italy ahead of his proposed loan move from Chelsea to AC Milan.
Sebastian Kehl says Shinji Kagawa would be welcomed back to Borussia Dortmund with open arms.
Willian is the club's top target to replace Gareth Bale, who was edging closer to a world-record move to Real Madrid on Thursday after Franco Baldini held discussions with the nine-time European champions.
Willian underwent a medical at Spurs earlier this week, but reports on Thursday night claimed that Jose Mourinho has attempted to gazump his former protege by bidding for the Brazil international.
Online bookmakers Sky Bet re-opened betting on the player's future having suspended the market earlier in the week and last night made Chelsea odds-on favourites to snap him up.
Mourinho claimed earlier this summer that Wayne Rooney was his only remaining transfer target, but the Chelsea boss now appears to have had a change of mind.
Villas-Boas, speaking just after Tottenham's 5-0 Europa League playoff win over Dinamo Tbilisi, said he knew nothing about Chelsea's apparent approach for Willian, but he conceded anything was possible regarding the transfer.
"We were just involved in a game so unfortunately I can't give you further information," the Tottenham manager said.
"I confirmed our interest in the player. Everything is possible, but I'm not aware of the circumstances because of our involvement in the (Dinamo) game. I don't want it to be a distraction over what we achieved here."
Madrid, meanwhile, seem so confident they are going to sign Bale that they appear to already be stocking replica shirts bearing the Tottenham forward's name.
The Spanish giants kept the number 11 free when they announced their squad numbers in pre-season and screen grabs of the club's official online shop appeared to show the option to buy a Bale replica shirt for 73 euros (£62).
Shortly after the screen grabs went viral, the site was down for maintenance.
If Bale does seal his move to the Bernabeu on Friday - as has been reported in the Spanish media - it will mark the end of one of the longest-running transfer sagas of the summer.
It will also give the Wales international the opportunity to shine in the Champions League, where he deserves to play following his stellar performances last season, when he scored 31 goals for club and country.
Villas-Boas' new-look team proved there might be life after Bale when they routed Dinamo in the first leg of their playoff game.
Andros Townsend put in a Bale-esque performance on the flanks, scoring a fine solo goal and setting up two more to put Spurs in charge of the tie ahead of Thursday's second leg.
"Andros has been working well in training, so we felt it was time to give him an opportunity and he did very well," Villas-Boas said.
"If we have the type of performance we had to today (from him) we can always count him.
"For all the young players we are bringing through the competition they face is extremely difficult and in my opinion, when you overcome that type of opposition you can only become a top player.
"He is doing it the right way he seems very focused after last year's experience."