World No.1 Naomi Osaka has withdrawn from the Qatar Open in Doha due to a back injury.
“I am sorry to have withdraw from Doha this year as I was looking forward to playing and seeing my fans there,” the Australian Open champion said in a statement.
“I wish everyone a great week and hope to see everyone next year.”
The 21-year-old has previously suffered with back trouble, missing last year's Hong Kong Open with the problem.
The tournament would have been her return to competition following her triumph in Melbourne.
The USA's CoCo Vandeweghe has also withdrawn due to a continuing ankle injury.
World No.3 Simona Halep, Karolina Pliskova, Angelique Kerber, and Kiki Bertens are still all set to compete.