A catalogue of injuries threatens to play havoc with the Australian Open and put more pressure on women's tour organisers to reform the playing schedule.

Injuries or illness have felled most of the women's top 10 in recent weeks, in what is either a hefty dose of bad luck or something more avoidable.

World number one Serena Williams is chief among the injury concerns after she pulled out of the Hopman Cup exhibition tournament with a sore knee.

But the 21-time Grand Slam-winner is not alone, with only her sister Venus and Flavia Pennetta -- who has retired -- unscathed among the women's top 10.

Simona Halep, Garbine Muguruza, Agnieszka Radwanska and Maria Sharapova have all pulled out of build-up tournaments because of injury concerns.

Meanwhile Petra Kvitova and Angelique Kerber have been hit by gastroenteritis, while Lucie Safarova is skipping Melbourne because of a problems linked to a bacterial infection.

While illness is largely uncontrollable, Williams, Halep and Sharapova are all still hampered by injuries which affected them last season, whose tail-end was unusually busy.

Problems on the men's side are also comparatively light, suggesting a link between the injuries and the women's tour -- whose schedule has repeatedly been criticised by players.

Incoming Women's Tennis Association Steve Simon has already promised "fundamental changes" to the demanding calendar after a rash of injuries and withdrawals towards the end of last season.

"Clearly one of the big issues that we have right now is dealing with... getting our athletes through the season healthy," he said at the WTA Finals in Singapore.
                  
Pushed to the limits                
                  
The women's season is particularly busy during its final months, when an "Asian swing" kicks in after the year's last Grand Slam, the US Open.

Last year, places were up for grabs until the last minute at the lucrative, eight-woman WTA Finals, prompting players to push themselves to the limits in a late dash for qualifying points.

Whether injuries have a major impact on the Australian Open remains to be seen, but there are certainly concerns over Williams, who has not played a competitive match since September.

The American great retired during her only match at the Hopman Cup in Perth, and Australian Open organisers will hope she meant what she said when she insisted she was "feeling great now".

Sharapova, injured for much of last season, has also expressed confidence about her recovery from a forearm problem which first surfaced in September and forced her to drop out of Brisbane.

Second-ranked Halep is having trouble shaking off an achilles injury which also affected her last year, but after withdrawing from Brisbane she played this week in Sydney.

World number three Muguruza retired from her first match in Brisbane with a foot problem, and fourth-ranked Radwanska withdrew from Sydney with a leg injury.

For women's legend Martina Navratilova, whose playing career lasted into her late 40s, "the number of injuries withdrawals is still too high".

"You got to think long-term. Maybe it's great to have all these tournaments but at the end of the day, if you don't have enough players playing, you got a problem," she said at the WTA Finals.