The Ivory Coast striker will be out for three weeks after
undergoing "minimal invasive surgery" on Friday.
It means he will not feature in the Community Shield clash
against Manchester United.
And he is a doubt for the Blues' Premier League opener with West
Brom a week later on August 14.
A Chelsea statement said: "The decision to perform the procedure
after his return from the World Cup was made to optimise his
rehabilitation.
"He is expected to return to full training in approximately
three weeks."