Chelsea manager Luiz Felipe Scolari has revealed striker Didier Drogba is set to miss the start of the season.Drogba, 30, has spent the summer recuperating from a knee injury and will not be fit for the Premier League opener against Portsmouth on 17 August."Didier will not play in our first game and will probably miss the second against Wigan," said Scolari."If there are no more problems he should be ready for the game after that, Tottenham on 31 August."However, Scolari concedes that the nature of Drogba's injury makes it difficult to predict exactly when the Ivory Coast star will return to full fitness.The Brazilian added: "When you have a knee injury, you just never know."I have been getting a progress report from the doctor every day."He's getting better and is working with a fitness coach back at the training ground."I hope he will be ready to start training next week but he will not play until he is in good condition."In the absence of Drogba, Chelsea will be relying heavily on Nicolas Anelka, who scored four goals in a 5-0 mauling of AC Milan on Sunday.Salomon Kalou is away at the Olympics and Scolari has hinted Andriy Shevchenko is not a contender to start the first game of the season.Source: BBC