Defoe scored 142 goals in 362 appearances for Tottenham over two spells at White Hart Lane before joining Toronto ahead of their 2014 MLS campaign.
The England international is now set to link up with Spurs' development squad for the next week.
"We can confirm that Jermain Defoe will train with our development squad for the next week to maintain fitness during MLS close-season," Tottenham posted on Twitter.
News of Defoe training with Tottenham is sure to spark further rumours that the former West Ham man is seeking a return to the Premier League.
QPR manager Harry Redknapp has spoken of his admiration for a player he managed at West Ham, Portsmouth and Tottenham, but admitted the club would struggle to sign him on a permanent basis.
Hull City boss Steve Bruce announced his interest in taking Defoe to the KC Stadium last week, while Leicester City have also been touted as a possible destination.
