British number one Kyle Edmund says he will do "everything he can" to be fit for the Australian Open after picking up a knee injury.
The 23-year-old Yorkshireman, ranked 14th in the world, has withdrawn from next week's Sydney International.
The event was set to be Edmund's final tournament before the first Grand Slam of the year, which starts in Melbourne on 14 January.
Edmund reached his first Slam semi-final at last year's tournament.
"I am disappointed that I won't be able to return to Sydney," he said.
"I need to focus on my preparations for the Australian Open and do everything I can to be fit for the first Grand Slam of the year."
On Wednesday, Edmund suffered a shock defeat by Japan's world number 185 Yasutaka Uchiyama, who won 7-6 (8-6) 6-4, at the Brisbane International.