Striker Salomon Kalou has conceded Chelsea could struggle when they lose a number of key players to the African Cup of Nations.
Kalou and Didier Drogba will be in action for Ivory Coast, while Jon Obi Mikel will play for Nigeria and Michael Essien will represent tournament hosts Ghana.
The key quartet could miss up to four Premier League games while away on international duty and Kalou has admitted he has concerns over Chelsea's ability to keep their title challenge on track.
He said: "Chelsea will be under-strength during the month of January because Drogba and Essien, who are very essential to their countries and to Chelsea, will be missing.
"Obi Mikel and myself will also be in Ghana to play for our countries.
"Hopefully when the competition finishes, we should be in a good position in the league so we can come and make the difference."
However, the former Feyenoord striker is relishing the prospect of playing in his first Cup of Nations.
"I am excited to represent my country," he added. "It is my first big tournament and hopefully we will win because we have very good players in the team.
"Our team is packed with experienced players who play in the biggest leagues in the world and also in European competition."