Roger Federer has undergone knee surgery after suffering an injury on the day after his Australian Open semi-final defeat.
The 17-time grand slam winner has forecast he will return to action "soon" but has pulled out of playing commitments for the rest of February.
Federer, 34, tore a meniscus last week, said a statement on his personal website, rogerfederer.com.
It occurred on Friday, following the previous day's four-set defeat to Novak Djokovic at the last-four stage in Melbourne.
How Federer suffered the setback was not detailed in the short statement.
Although he will not compete this month at the ABN AMRO World Tennis Tournament in Rotterdam and the Dubai Duty Free Tennis Championships, the Swiss player will hope to be fit for the Masters 1000 events in Indian Wells and Miami in March.
Federer said: "I am so disappointed to have to miss Rotterdam and Dubai as they are two of my favourite tournaments on the ATP World Tour.
"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."