PARIS (AP)—Top-ranked Rafael Nadal withdrew from the Paris Masters on Friday because of a shoulder injury that will keep him sidelined for at least a week.

Nadal said in an e-mail sent out by his management team that he was suffering from “a small case of tendinitis in my left shoulder which came about through forcing my serve too much during training this week.”

“I am very sorry not to be able to play the Paris-Bercy tournament this year,” Nadal said.

The Spaniard said the injury wasn’t serious, but he had been advised by doctors that he needed six or seven days rest with intensive rehabilitation treatment. Nadal is scheduled to play in the season-ending ATP World Tour Finals in London from Nov. 21-28.

The ATP tour said Nadal would still make an appearance at the Paris tournament and would discuss his injury further at a news conference Sunday or Monday.

“It’s always a blow for a tournament to lose Nadal,” event director Jean-Francois Caujolle said. “We still have nine of the 10 best players in the world and I don’t think the tournament has been hampered by his withdrawal, even though it would have been better to have him.”

Nadal recently said he was feeling some fatigue from a successful season in which he won the French Open, Wimbledon and the U.S. Open. Nadal has not played since a third-round defeat to Jurgen Melzer at the Shanghai Masters on Oct 14.

With Nadal’s withdrawal, Roger Federer has been given the No. 1 seed and will start against the winner between Nicolas Mahut and Richard Gasquet.

The tournament starts Sunday.