Roger Federer, sidelined from the tour while rehabbing a knee injury, says he is keeping up with the U.S. Open.

Federer spoke to the ATP tour website from the mountains in Switzerland, and noted that he would prefer to be in Flushing Meadows.

"Of course it hurts,” he said. “I would love to play on Arthur Ashe. I would love to hear the roars of the crowd. Just being in the city would be amazing, being there with all the other players.”

However, he indicated that he is recovering from the injury that prompted him to wrap up his season prematurely following Wimbledon. He had surgery on his knee following the Australian Open, but appeared to be experiencing ongoing problems at subsequent events.

"I'm doing fine,” Federer said. “I'm healthy, and I'm enjoying a great time with my family. And I catch myself, very often, checking scores of what's going on.”

Federer is No. 4 in the rankings.