World No. 3 Roger Federer underwent successful arthroscopic knee surgery in Switzerland on Wednesday to repair a torn meniscus and will miss two tournaments this month.
The Swiss suffered the injury the day after his Australian Open semifinal defeat to Novak Djokovic last Thursday night.
The 34-year-old Federer said he would be forced to withdraw from ATP events in Rotterdam and Dubai.
"I am so disappointed to have to miss Rotterdam and Dubai as they are two of my favorite tournaments on the ATP World Tour," Federer said in a statement. "While this is an unfortunate setback, I feel grateful that up until now I have remained mostly healthy throughout my career. My doctors have ensured me that the surgery was a success and with proper rehabilitation, I will be able to return to the Tour soon."
The statement did not specify which knee is injured.
The 17-time Grand Slam champion's next scheduled tournament is in Indian Wells, Calif., starting March 7.
"I apologize to my friends in Rotterdam and Dubai, as I was very much looking forward to playing those events," Federer said on his Facebook page.