"In an attempt to prevent injury after the long final in Paris, I cannot defend my title at the Gerry Weber Open in Halle. Gerry and Ralf Weber have always been so hospitable over the years and I love playing there. I look forward to returning in 2008," the World's number one was quoted saying on his official website.

Federer has been used to win the German grass-court event for the past four years before going on to claim the Wimbledon crown on each occasion.

"Of course we really regret it," co-organizer Ralf Weber said at a news conference on Monday. "Roger had played here for the last seven years and he gave everything for the tournament.

"I know Roger took the decision with a heavy heart. He will fly to Zurich, rest a few days and will probably fly straight to London."

Otherwise Federer kept his top seed in the ATP Ranking despite losing to Rafael Nadal in the Final of the French Open on Sunday.

Federer is still in the lead with 7515 points while Nadal is second with 5225 points.