Russian Marat Safin has become the latest player to drop out of the upcoming SAP Open, tournament organisers announced on Tuesday.
The former US Open and Australian Open champion has withdrawn from the hardcourt event due to a stress fracture in his right leg.
The 28-year-old, who also is dealing with a stomach flu, was unable to play in Russia's Davis Cup win over Serbia last weekend.
"The SAP Open is disappointed to lose a player as exciting and as popular with the fans as Marat Safin," tournament director Bill Rapp said.
"We wish Marat a speedy recovery and look forward to seeing him compete on the ATP Tour later this season."
Safin reached the quarter-finals at the event last year.
The Russian will also miss an exhibition match against Pete Sampras next Monday. He will be replaced by former world number two Tommy Haas of Germany.