The Brazilian midfielder has been out of action for six months after suffering a serious knee injury in January.
"Sandro hit six months last week and we are on plan," Villas-Boas told the club's official website. "He's made an excellent recovery and we're very happy with him.
"One more week and he'll join the group and he will also join us for full training in Hong Kong."
Spurs start their pre-season campaign underway on Tuesday, when they face Swindon Town at the County Ground.