Roger Federer is optimistic he will be fit to play in the season-ending Masters Cup in a fortnight as he recovers from a torn ankle ligament.
The world number one was on crutches for two weeks after sustaining the injury in training earlier this month.
"I'm walking now," he said. "I'm taping the ankle a lot, but that helps me to put weight on it.
"I'm optimistic, but it's hard to tell. Shanghai means everything. That's what I'm working on right now, I'm hopeful."
Federer is among several qualifiers struggling to be fit for the event starting on 13 November.
Marat Safin has already been ruled out with knee problems, Andre Agassi has been inactive since losing the US Open final to Federer while Lleyton Hewitt could miss it to attend the birth of his first child.