Veteran batsman Mike Hussey was handed a Cricket Australia lifeline overnight as its replacement for injured pace bowler Doug Bollinger.
NSW left-armer Bollinger was sent home from the subcontinent with an ankle injury a week ago and the selection panel has opted for an extra batsman.
However the Victoria quick Dirk Nannes will also join the squad as a standby player.
The 2007 World Cup winner Hussey was controversially left out of the original 15-man squad as he recovered from hamstring surgery but made a comeback in a Shield game for Western Australia during the weekend, scoring 19 and 11 against Queensland in Perth.
He will speak publicly about his inclusion on Monday morning before his departure.
"Michael has successfully recovered from major hamstring surgery and is seen as someone who is capable of assisting Australia as we strive to win this tournament," chairman of selectors Andrew Hilditch said in a statement.
"His skill, experience, ability against spin and the fact that he provides a left-hand option in the middle order is seen as critical in our World Cup defence now that he has successfully recovered from injury.
"Dirk will train with the Australian World Cup squad and be fit, available and acclimatised in the event of an injury to a fast bowler, in particular a new-ball fast bowler, in the final stages of this tournament.
"Dirk has been in excellent form and played a critical role in Victoria's recent (one-day) cup victory and will be an excellent replacement bowler in the event of injury to a key opening bowler."
Unbeaten Australia have Group A matches against Kenya and Canada on March 13 and 16 in Bangalore.
Ricky Ponting's men are not expected to resume training until Wednesday.
Mike Hussey's likely inclusion in the selected side against the World Cup minnows at No.5 in the batting order could mean Cameron White loses his place in the lineup, with No.6 David Hussey also a potential candidate to make way for his older brother in the 11.
Australia also play Pakistan in Colombo on March 19.
After thumping Zimbabwe and New Zealand last month, Australia's third game in Group A was washed out on Saturday night in Colombo after Sri Lanka made 3-146 from 32.5 overs.
The defending champions will be determined to improve on their form in the warm-up matches in Bangalore last month when they lost consecutive games to India and South Africa on turning pitches.