The draw for the group stage of the ATP Finals in London will take place this Monday, but Rafael Nadal won't feature in it as the Spaniard is ruled out with injury.
Rafael Nadal announced Monday he has cut his season short because of more health setbacks.
The Serb is back on the top of the pile for the first time in two years, at the end of a roller-coaster season for the 14-time major victor. An abdominal problem kept him out of Paris Masters last week, and he needs an operation on his right ankle.
His decision means he will lose the end-of-season world No 1 ranking to Novak Djokovic.
His plan for the Masters is two happy: John Isner was only supposed to be replacing and that gets finally a place holder for the tournament in london.
"Reflecting on what I've been through in the a year ago, it's quite a phenomenal achievement", said Djokovic, who was No. 2 last week and hadn't been No. 1 since November 2016.
Cape Town - It's a case intriguingly of what he can achieve, what he can't achieve and what he will achieve when top South African tennis player Kevin Anderson competes in his first ATP Finals next week.
With Nadal out of competitive tennis for the rest of the year, Novak Djokovic is assured of ending the season on top of the world rankings.
"This way I hope to be in full condition for next season".
Djokovic, 31, underwent elbow surgery in January and slipped to 22nd in the world after a depressing quarter-final exit at Roland Garros in June, which left him briefly threatening to skip Wimbledon.
Nadal withdrew from the following week's Cincinnati Masters and was then forced to bring a premature end to his US Open semi-final with Juan Martin del Potro due to a knee injury.
The left-hander excels on the dirt and has won a staggering 11 French Open titles.
He finished 2011 with a 70-6 win-loss record, a haul of 10 tournament victories and the year-end number one spot for the first time.