The 29-year-old midfielder has been an integral part of the Spurs ever since coming to England two years ago, but has been strongly linked with a move back to Germany this summer.
The Netherlands international's future has been up in the air this summer, with reports linking him with a return to Germany after a hugely successful three-year spell with Hamburg, and with the club's sporting director Frank Arnesen admitting a deal would interest the club.
Villas-Boas refused to rule any departure for Van der Vaart in the future, though, stating that any move that may happen would most certainly be done on his own terms and only with his say so.
"In football you never know. Anything can happen but he’s a player we are counting on," he told reporters. "This is football. If I let Rafa go it’s because I’ve allowed him to go. It’s not because someone is forcing me to."
The Portuguese boss was eager to play down the importance of Van der Vaart's absence from the starting lineup during the club's opening game with Newcastle, arguing that it was merely a fitness issue after an injury picked up during preseason.
"He’s a player I obviously count on," Villas-Boas continued. "Rafa was very unlucky because when he came back from his vacation after the Euros he got injured in the game against LA Galaxy so he missed most of our preseason in America.
"He was a player that came back to us late so the selection was pretty straightforward for Gylfi Sigurdsson in the game against Newcastle. Now Rafa has trained with us all week and he’s looking strong and is in contention.
"He’s a player of great importance for us. I’m not sure if Hamburg are interested but he’s a player who at the moment is not for sale."
Follow GOAL.COM USA on