Australia suffered a blow Monday when specialist batsman Damien Martyn was ruled out of the World Cup semi-final against Sri Lanka with a fractured finger.
Coach John Buchanan said: "He's out of tomorrow's game and he will be reviewed in the next couple of days, depending on the side's progress."
The number four batsman hurt his right index finger while fielding in the five-wicket win against Kenya on Saturday in Durban. The fracture was revealed after an X-ray on Monday.
Australia have already lost leg spinner Shane Warne (failed drugs test) and fast bowler Jason Gillespie (heel injury) from their World Cup squad, while fellow paceman Shane Watson pulled out just before the event with an injured back.
The 31-year-old Martyn, a key part of the Australian top order, has made three half-centuries in seven World Cup innings, at 47 runs a visit. He averages 40.62 in 122 one-day internationals and more than 46 in tests.
Jimmy Maher is the only specialist reserve batsman in the squad -- he is also the back-up wicketkeeper -- but he has only played two Cup games, averaging 17.5.
Australia, who have won 15 one-dayers in a row, could instead choose to play two all rounders, Andrew Symonds and Ian Harvey, against Sri Lanka.
The Sri Lankans were the last side to beat Australia in a one-dayer, in Sydney in January, but have lost four of their last five meetings, including a World Cup Super Six match in Centurion on March 7.