30-year old striker Defoe has been linked with a possible summer move to QPR whilst 23-year old Icelandic midfielder Sigurdsson's role looks clouded following the summer arrivals of the likes of Paulinho and Nacer Chadli.
However, Villas-Boas has assured the pair that they are in the plans of the White Hart Lane club: "They are players we count on 100 per cent. Sigurdsson is completely in our plans.
"Defoe is a hero for Tottenham and has been doing well. He faces competition which he has always faced during his career."