The world number two, who has not played since winning his fifth consecutive US Open title last month, revealed on Wednesday he needs a break from tennis.

"(This) has been a tough year for me as I was always playing catch-up after being diagnosed with mononucleosis at the beginning of the year," said Federer, who lost the world number one ranking to Rafael Nadal in August after holding it for a record 237 consecutive weeks.

"I feel fortunate to be healthy again, but I want to remain at the top of the game for many more years to come and go after the number one ranking again."

Federer, 27, added he is not sure when he will return to the ATP Tour, but hopes to be back before the end of the year.