Roger Federer is aiming to be fit for next year's Australian Open after injury wiped out the last half of his 2016 season.
Federer, 35, has been out of action since late July - his last match was a Wimbledon semi-final loss to Milos Raonic.
The 17-time Grand Slam winner had surgery in February before a back issue ruled him out of the French Open.
"I'm working for the Australian Open," the Swiss said. "I'm doing well."
"I never thought I'd have a year like this. I've learned a lot from this year," added Federer, who missed the Rio 2016 Olympics and will be unable to go for a sixth US Open title when the tournament begins on 29 August.