"It's really only Novak who can say "If I play as well as I have the last three months then maybe I can win the ATP Finals as well", the Swiss, who begins in Lleyton Hewitt group against Japan's Kei Nishikori on Sunday, told reporters.
'I don't see a reason to change, unless there is somebody else, a city that really wants it badly and is willing to come in and really support the Tour in a major way for many years to come.
The 31-year-old, who slipped to 22nd in the world in May, admitted that after his surgery it looked improbable that he would finish the year as number one.
"I've played well since 2011 even though I didn't end up winning the World Tour Finals any more but I feel like I've done well and it doesn't feel like it's that long ago".
Nishikori has not been able to find the answers to Federer's game in their two recent meetings so that may affect him mentally here so he must try and treat this meeting as a clean slate.
The baseliner's effort to reach the final of the Next Gen ATP Finals decider is yet another milestone for the Sydneysider.
The tournament opens on Sunday afternoon when Wimbledon finalist Kevin Anderson takes on French Open runner-up Dominic Thiem, but fans will have to wait until Monday before Djokovic plays his first match.
"It's extra special this season because of the whole journey I've been through the past 15 months, particularly the last eight months, after surgery in February".
"I've had phenomenal success here and I should be the last one to talk about moving it". "It turned out to be a flawless five months".
Former champion Andy Murray, still making his way back from injury, and defending champion Grigor Dimitrov are other star names missing. "Been pretty close throughout my career, but it never happened". "However, since the problem in the abdominal muscle also prevents me from playing in London, we take advantage of the moment to remove the free body and avoid future problems", the Spaniard explained.
On facing Djokovic first up, he said: "I'm up against it for sure".