Rafael Nadal has pulled out of the season opening event in Abu Dhabi to concentrate on being fit for the Australian Open.
The 31-year-old, who is back as world number one after a hugely successful 2017, had missed the ATP Finals in London last month and was intending to return to play the Mubadala World Tennis Championships as he begins preparations for the first Grand Slam of next year.
However, he is now revising his plans, telling the Mubadala tournament website: "It was a tough 2017 and I need to take my calendar in a different way in order to be ready.
It was a tough 2017 and I need to take my calendar in a different way in order to be ready.Rafael Nadal
"For this reason, I have sadly announced to the organisers and now to you fans that I won't play this time in Abu Dhabi."
Nadal won the French Open and the US Open last year while Roger Federer won the other two Grand Slams, beating Nadal in this year's Melbourne final.
Nadal is 9/2 to win early next year with Federer 7/4 and the returning Andy Murray 1212/1.
The Spaniard will be replaced in Abu Dhabi by compatriot Roberto Bautista Agut while others to withdraw from the event are Stan Wawrinka and Milos Raonic, two players who, along with Murray and Novak Djokovic, missed the latter part of last season with injury.
Another seeking to return this year is Kei Nishikori, who has been out of action with a wrist injury for four months and he has pulled out of the Brisbane International event as he delays his comeback.
Meanwhile, US Open champion Sloane Stephens is out of the women's event in Brisbane as she recovers from a knee injury.
Serena Williams, winner in Melbourne this year, is 1212/1 to win again in 2018 after returning to the sport from maternal leave.
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