Roger Federer has undergone arthroscopic knee surgery and will miss a month of tennis.
The former world No.1 will miss tournaments in Rotterdam and Dubai this month due a torn meniscus in his knee.
"I want to inform you that yesterday I underwent arthroscopic surgery on my knee," Federer said in a statement.
"I injured my knee the day after the semi-finals in Australia. After getting tests done when I returned home, it was determined that I had torn my meniscus.
"I apologize to my friends in Rotterdam and Dubai, as I was very much looking forward to playing those events. While this is an unfortunate setback, I am encouraged and grateful that my doctor said the procedure was a success.
"I am looking forward to attacking the rehabilitation process this afternoon with my team and working hard to get back out on tour as soon as possible."
At this stage Federer is scheduled to return to the court in Indian Wells in California on March 7.
