Tayla Vlaeminck under injury cloud
Vlaeminck, 21, whose pace was expected to be an important element of Australia's attack in their title defence, was sporting a 'moon boot' on her right leg ahead of the first match in Sydney on 21 February.
According to cricket.com.au, she is reportedly suffering from a stress-related foot injury. She was seen wearing the walking aid at the Sydney airport and at a pre-tournament event on Wednesday. She did not feature in Australia's four-wicket warm-up win against South Africa in Adelaide on Tuesday.
Vlaeminck's teammate Ellyse Perry said the full extent of the injury would be known in about 24 hours, but "it isn't positive".
South Africa's bowlers gave Australia some nervous moments in their Women's T20 World Cup warm-up match, before the hosts won by four wickets.
"'Tay' unfortunately has a new fashion accessory to her foot, which the medical staff are working through," Perry said. "Anything that requires a moon boot isn't overly great. The whole squad has their fingers and toes crossed for Tay but I don't think it's overly positive. We should know in the next 24 hours.
"From a players' point of view, we're very supportive of Tay. She's an important member of our squad and we just want to wish her all the best."
Vlaeminck, who can hit speeds of 120kph, has been in form in the run-up to the tournament, picking up seven wickets in three games of the tri-series with India and England. She proved to be particularly effective against India, who found her fiery pace difficult to contend with.