Roger Federer unconcerned by mounting injury toll as Andy Murray withdraws from US Open
British world number two pulls out of grand slam due to hip injury to join Novak Djokovic, Stan Wawrinka and Kei Nishikori in skipping Flushing Meadows

Roger Federer does not believe the gruelling professional tennis schedule should be shortened despite a rash of injuries ahead of the US Open.
The 19-time grand slam champion made his comments a few hours before world number two Andy Murray announced he was pulling out of the US Open due to the hip injury that hampered him during his unsuccessful defence of his Wimbledon title in July.
Murray, 30, joins 12-time grand slam winner Novak Djokovic, 2016 US Open champion Stan Wawrinka and Japan’s Kei Nishikori in missing the tournament through injury.
“The guys who are hurt lately, it’s mostly because they are 30-plus,” 36-year-old Federer said.
“I don’t think there needs to be that much addressing because the players, they have the option not to play as much as sometimes they have to or want to.
“I don’t think the tour is doing much wrong, to be quite honest.”