Petr Cech will miss the season's opening game against West Bromwich Albion following an injury in training.
The 28-year-old goalkeeper tore a calf muscle in his right leg in an training ground sesion yesterday and will obviously miss the Community Shield match against Manchester United on August 8 and all the remaining pre-season matches in Holland and Germany.
He is expected to be out for a month. Chelsea play Wigan away following the season's home match on August 14.
Chelsea boss Carlo Ancelotti will have a selection headache to decide which of his reserve goalkeepers gets the nod.
Ross Turnbull and Hillario each has 30 minutes in Saturday's 1-0 against Crystal Palace, with Turnbull looking the more nervous.