The African Cup of Nations starts in January, with the Ivory Coast's Didier Drogba and Michael Essien of Ghana almost certain to be away from Stamford Bridge for the entire duration of the tournament.
Mourinho told the News of the World: "We are never happy with the African Cup of Nations in January.
"African players are excellent technically and are natural fighters but when you have a lot of them you have to say stop, no more.
"Losing them can kill your team at a crucial time. If someone asks me do I want more African players, I'd say no."
Meanwhile, new boy Claudio Pizarro insists he has not joined the club to live in Drogba's shadow.
The 28-year-old Peruvian, signed on a free from Bayern Munich, said: "I am not here to be a substitute for Drogba. My dream is to be the No 1 striker at Chelsea."