World number one Roger Federer [ Images ] has pulled out of next week's Japan [ Images ] Open due to fatigue.

Federer, who won the Tokyo title last year, said he had yet to recover after winning his fourth consecutive US Open [ Images ] title and playing for Switzerland [ Images ] in the Davis Cup earlier this month.

"I am so disappointed that I have to withdraw from the Japan Open," Federer said in a statement.

"At this point I have still not physically recovered 100 percent from the US Open and Davis Cup.

"Thus my doctor advised me that in an effort to avoid the risk of serious injury, I should not play a tournament for at least 10 days."

Federer's late pullout for the October 1-7 Japan Open leaves world number eight David Ferrer as the tournament's highest seed following the Spaniard's late entry into the men's draw.

Wimbledon [ Images ] champion Venus Williams [ Images ] was also added to the women's draw on Friday.