The 31-year-old, who landed in Toronto on Saturday, missed all of the MLS team's pre-season due to commitments to Tottenham Hotspur and England.
Defoe was on the bench for England's friendly against Denmark last Wednesday at Wembley but did not get a chance to earn a 56th cap in the 1-0 win over Denmark.
Then sidelined by a hamstring injury, the former Spurs star said his farewell to the fans at White Hart Lane on Feb. 27 during halftime of a Europa League match against FC Dnipro Dnipropetrovsk.
Defoe left Spurs with 143 goals to his credit, behind only Cliff Jones (159), Martin Chivers (174), Bobby Smith (208) and the legendary Jimmy Greaves (266) in the club record book.
Defoe also leads all Spurs scorers with 23 goals in European competition.
The English forward will be welcomed by Toronto manager and former Spurs teammate Ryan Nelsen, who has seen his strike force hampered by injury.
Brazilian newcomer Gilberto has been slowed by a quadricep injury while Bright Dike is gone for the season after tendon surgery. That leaves Defoe, Andrew Wiedeman and Dwayne De Rosario as attacking options.
Nelsen said the participation of Defoe and Gilberto in Saturday's opener in Seattle will depend on how they look this week.
"I can only really give you proper answers when we've got them both back in training and we can really see where they're at," he said.
Defoe, while he has not played much recently, is likely ahead of Gilberto because the Brazilian was out of season when he arrived at training camp. But Nelsen is not likely to rush either to action before they are ready,
Defoe was 21 when he joined Tottenham from West Ham in February 2004, scoring on his debut against Portsmouth. He left for Pompey in January 2008 but returned a year later.
Defoe only made two appearances for Spurs since his transfer move to Toronto was announced. He scored Jan. 11 as a substitute in a 2-0 win over visiting Crystal Palace before coming on for five minutes in a 1-0 win over Everton on Feb. 9.
Defoe, who has scored 19 goals for England, hopes to earn a spot in Roy Hodgson's World Cup squad. His competition includes Wayne Rooney and Danny Welbeck of Manchester United, Daniel Sturridge of Liverpool, Rickie Lambert and Jay Rodriguez of Southampton and Andy Carroll of West Ham.
England has three friendlies left before the World Cup — Peru at Wembley on May 30 before games in Miami against Ecuador and Honduras.
Toronto already expects to lose Brazilian goalkeeper Julio Cesar and American midfielder Michael Bradley to World Cup duty.
Defoe, Bradley, Gilberto, Cesar and De Rosario are key off-season acquisitions for a Toronto team desperate to make the MLS playoffs after seven years of failure on the field.
Other newcomers include fullback Justin Morrow and Bradley Orr and Brazilian midfielder Jackson.
Defoe will be able to renew acquaintances with his former Spurs teammates when Toronto FC and Tottenham will meet July 23 in a friendly at BMO Field.