World number four Maria Sharapova's Australian Open preparations have been dealt a blow after she was forced to withdraw from the WTA Brisbane International due to a left forearm injury.
Tournament organisers made the announcement on Tuesday, hours before the defending champion was due to play fellow Russian Ekaterina Makarova in the first round.
Sharapova, who defeated Ana Ivanovic in last year's final, will be replaced by a lucky loser.
"I hurt my forearm in practice a couple days ago and need to precautionary withdraw with the Aus Open starting," Sharapova said via the Brisbane International's official Twitter account.
"Brisbane Tennis is such a special event especially being defending champion. I look forward to seeing all my fans next year."
Sharapova's withdrawal from the eighth edition of the hardcourt event in Brisbane comes after a difficult year in 2015, which saw her pull out of the US Open, Fed Cup semi-final, Rogers Cup and Cincinnati and China Opens.
The 28-year-old also withdrew mid-match at the Wuhan Open in September.