Manchester United winger Nani has arrived in Istanbul to complete a move to Fenerbahce.
Liverpool are set to confirm the appointment of Sean O'Driscoll as assistant manager on Monday.
Toronto FC manager Ryan Nelsen, who played with Defoe at Spurs two years ago, this week declared his interest in signing the striker.
Defoe has 18 months left to run on his current deal and is second choice at Tottenham despite finding the target eight times this season.
Villas-Boas has preferred to use £26million man Roberto Soldado ahead of Defoe, with the 31-year-old being used primarily for the domestic and European cup competitions.
Despite this, Villas-Boas still values Defoe highly and does not want to let the diminutive hitman leave.
"I have seen in the press that there is reported interest (from Toronto), but we want the player to stay on and hold on to those last years of his contract," the Spurs boss said.
"In the end the player is committed to the club and the club is committed to the player."
Defoe recently spoke of his frustration at a lack of first-team opportunities at Spurs - something which could cost him dear in the fight for a place in England's World Cup squad.
But Villas-Boas believes the player is determined to win back his place in the side after becoming joint-record scorer for the club in Europe this season.
"The player at the moment is our top goal scorer and he is chasing the European record for the club as well which is important for his individual motivation," Villas-Boas said.
"I think he is extremely happy, not only because of what he has achieved, but also because of the smile on his face.
"He has had a better start than he had last year. That is an impressive goals tally and he is a player that everyone cherishes."
Nelsen, who played for Spurs in Harry Redknapp's final six months at the helm, lavished praise on Defoe during an interview this week, admitting he would be an "unbelievable" signing for the Canadian club.
Villas-Boas says he is not concerned at Nelsen's revelation that he regularly speaks to his former Tottenham team-mate.
"I'm fine with this," the Portuguese said.
"I have no problem (with it). In the end situations like this can happen."
Defoe will be pushing for a place in Tottenham's starting XI on Sunday when the London club travel to Everton.
Tottenham were in the midst of a strong run last season when they visited Goodison Park and all looked to be going well when the Londoners took the lead halfway through the second half.
Everton hit back with two late goals to steal the victory, however.
Those three points would have been enough to edge Tottenham in to the Champions League last season, so Villas-Boas knows his team cannot afford to throw points away again this season.
"We've spoken about (last year's) result as the deciding factor for us not making it into the Champions League because everything changed quite dramatically," Villas-Boas said.
"It serves us as a lesson to be kept aware of and it's not something we want to see again."
Villas-Boas' side will have to stop Romelu Lukaku if they are to come away with something from Goodison Park this time around.
Lukaku has scored five goals in seven games since joining on loan from Chelsea, where he used to work under Villas-Boas.
The Belgian was furious with his treatment by Villas-Boas during his time at Chelsea, but the two have since buried the hatchet.
Villas-Boas has been impressed with how he has developed since his successful loan spell at West Brom last term.
"The player did extremely well last season and has continued to do well for Everton. The potential is there," Villas-Boas added.
"We all recognise he can become an influential striker in the future.
"Chelsea's standards are very, very high so the jump will be very difficult for him, but he has shown he can cope with the Premier League and it's another step up for him at Everton."