"The ICC has confirmed that the Event Technical Committee of the Cricket World Cup has approved Peter Handscomb as a replacement player for Shaun Marsh in the Australia squad for the remainder of the tournament," the ICC said in a statement.
"Marsh has suffered a fracture to his forearm which will require surgery after being struck while practising in the nets today."
All-rounder Glenn Maxwell was also hit on the forearm by a Mitchell Starc delivery but coach Justin Langer was optimistic about his chances of playing on Saturday.
"Glenn Maxwell also underwent scans after he was struck on his right forearm in the nets," Langer said in a statement.
"The scans have cleared Glenn of any serious damage and we'll continue to monitor him over the coming days. We are hopeful he will be fit to perform for us on Saturday against South Africa."
Handscomb, 28, has played 21 one-day internationals for Australia, with a century and four fifties to his name.
"Pete is a like-for-like player, in terms of batting in the middle order, and he performed very well for us during our recent tours in India and the UAE (United Arab Emirates)," Langer added.
Australia, who lead the standings, have already sealed a semi-final spot.
(Reporting by Rohith Nair in Bengaluru; editing by Clare Fallon)
