Chelsea striker Didier Drogba will be ruled out for up to five weeks after undergoing a knee surgery on Saturday. Drogba stated that he could just catch the upcoming 2008 African Cup of Nations in Ghana, which will kick off on January 20th. "My unavailability will be between one month and five weeks, considering healing and rehabilitation," said the Ivory Coast skipper. "I am very annoyed to miss the series of matches with Chelsea."