Chelsea look set to be without Didier Drogba for the start of the season after the Ivoroy Coast striker underwent a groin operation, dpa reported.
The 32-year-old had what was described as "minimally invasive" surgery and is expected to return to full training in about three weeks.
That would mean he would miss the Community Shield match against Premier League champions Manchester United on August 8 and put him in doubt for Chelsea's first matches of the league season.
Manager Carlo Ancelotti is already without goalkeeper Petr Cech for a month while defender Alex and new signing Yossi Benayoun are both struggling with injury.