The 23-year-old, who joined Madrid during the summer from Borussia Dortmund, has yet to make his competitive debut for Los Blancos because of a knee injury.
However, Mourinho has anticipated that he will be able to select the Turkish international in a fortnight.
"We hope that Sahin will be back with us in two weeks. The international break is taking place now, which is good for his recovery," Mourinho is quoted as saying by Marca.
Sahin has made 26 appearances for the Turkish national team.