Rafael Nadal has announced his withdrawal from the 10th staging of the Mubadala World Tennis Championship (MWTC) in Abu Dhabi, and will be replaced by Spain’s Roberto Bautista Agut in the six-man competition.
The world No 1 had won the tournament the past two years, and is the event's most successful player having lifted the title four times in the past.
But he will now be absent from the event, which takes place at Zayed Sports City Tennis Stadium between December 28-30.
The Spaniard said that the demands of his 2017 schedule, where he won two grand slam titles at the French Open and the US Open and returned to world No 1 had meant he needed more time to recover for 2018 then he had first expected.
“I am very sorry and disappointed to announce that I won’t be competing this year at the Mubadala World Tennis Championship," he said in a statement. "This would have been my ninth participation in the tournament where I love to play and marking the beginning of my season.
“It was a tough 2017 and I need to take my calendar in a different way in order to be ready. 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.
"I really want to thank them for understanding and I am sending a special warm message to my fans in the UAE and in Abu Dhabi in particular."
While not referenced in his statement, Nadal had ended his season early at the ATP World Tour Finals in London in November with a knee injury after playing just one match. This had come after he had also missed the Paris Masters with the same issue.
Bautista Agut, has ended four straight seasons in the top 25 in the world, has won two ATP titles in 2017, winning in both Winston-Salem and Chennai.
The world No 20 has six career titles to date, with another memorable career victory coming over then world No 1 and fellow Mubadala participant Novak Djokovic to reach the 2016 ATP Masters 1000 Shanghai final.
The rest of the field in Abu Dhabi is now made up of Djokovic, Bautista Agut, Dominic Thiem, Kevin Anderson, Pablo Carreno Busta and Andrey Rublev.
There was no news on Saturday morning as to whether the schedule for the event would now be redrawn. Nadal had been top seed, and along with Djokovic had been due to receive a bye to Friday's semi-finals.