Ricky Ponting is 'extremely doubtful' to take any further part in Australia's ICC World Twenty20 campaign.
The 32-year-old pulled his hamstring in the six-wicket defeat to Pakistan on Tuesday.
Ponting will now definitely miss the semi-final decider against Sri Lanka live on Sky Sports 1 from 8.30am on Thursday, and looks set for a two-week lay-off.
Should Australia progress to Saturday's semi-finals then Ponting could yet feature again in the tournament, depending on how his hamstring responds over the next 48 hours.
"Ricky has not been ruled out of the tournament yet," Australia's media manager Lachy Patterson told Reuters on Wednesday.
"His hamstring will be assessed over the next 48 hours and as soon as a decision is made by the medical staff, a statement will be issued by Cricket Australia."
Ponting has managed 61 runs in four innings during the Twenty20 tournament held in South Africa.
Vice-captain Adam Gilchrist will now take over the leadership role on the field.
His first game in charge will be a repeat of the World Cup final earlier this year which saw Australia beat Sri Lanka to lift the trophy for a third straight time.