Serena Williams: the seven-time women’s champion is unable to defend her crown. Saying she “needs more time” before returning competitively after having her first child last September.
Andy Murray: The former world No.1 and five-times runner-up has returned to Britain to consider surgery. Having not played since Wimbledon because of a chronic hip injury.
Kei Nishikori: The former world No.4 and US Open runner-up has succumbed to a wrist injury.
Svetlana Kuznetsova: The dual grand slam champion and world No.12 will miss the women’s event with a wrist injury.
Sania Mirza: India’s premier doubles player will miss out due to an ankle injury. Sania is suffering from a condition called jumper’s knee in her right leg.
In Doubt
Rafael Nadal: the world No.1 continues to battle a knee injury that forced his withdrawal from Brisbane. Still likely to start but no guarantees.
Novak Djokovic: The six-times Open champion hasn’t played since Wimbledon. And will make a call after testing his elbow in exhibition events at Kooyong and Melbourne Park.
Stan Wawrinka: The 2014 Australian Open champion has been out of action from 6 months. As he battles a knee injury that will restrict his build-up to next week’s one- night Tie Break Tens.
Victoria Azarenka: The two-time champion and former world No.1 remains locked in a custody battle that is preventing her son leaving California.
Struggling
Garbine Muguruza: Severe cramps forced the reigning Wimbledon women’s champion to retire from Brisbane International, but has since been cleared to play in Sydney next week.
Caroline Garcia: The world No.8 retired from her first-round match in Brisbane with a back injury.
Johanna Konta: The world No.9, a semi-finalist in Melbourne two years ago, retired from her quarter-final in Brisbane with a hip injury. And is unsure whether she will defend her Sydney International title next week.