Mardy Fish, the No. 23 seed, has withdrawn from the 2012 US Open due to health concerns. Roger Federer advances to the quarterfinals via walkover.
“I regret that I have to withdraw from the US Open for precautionary measures," Fish said in a statement. "I was reluctant to do so, but am following medical advisement. I had a good summer and look forward to resuming my tournament schedule in the fall.”
Federer expressed his best wishes for Fish's health and next faces No. 6 Tomas Berdych in the quarterfinals.
"I am really sorry for Mardy. I just want to wish him a speedy recovery. We all want to see him back on tour soon," Federer said. "It will be a tough match against Tomas. We have played many times in the past and he has always been a tough opponent. I will have to continue to serve well and dictate the points."
For today's schedule, the Marin Cilic-Martin Klizan match has been moved to Arthur Ashe Stadium, not before 3 p.m. ET.