Melbourne: Australia called up uncapped batsman Usman Khawaja on Tuesday as cover for captain Ricky Ponting, who is nursing a broken finger ahead of the crunch Melbourne Ashes Test.

Selectors said they were showing an "abundance of caution" in adding Khawaja to the squad, adding they were confident Ponting will play in the clash against England starting on Boxing day.

"While the NSP (National Selectors Panel) are confident Ricky Ponting will be available for the fourth Test, through an abundance of caution we have named Usman Khawaja as the standby player," chief selector Andrew Hilditch said.

Usman richly deserves this opportunity following his excellent form at domestic level last season and continuing on this season.

Pakistan-born Khawaja, 24, who plays for New South Wales, is yet to break into the team after becoming the first Muslim to be selected for an Australian Test squad in June.

Ponting has pledged to play in Melbourne despite suffering a small fracture to his left little finger while trying to take a catch during Australia's crushing win in Perth, which levelled the series at 1-1.

Khawaja, who will join the squad on Wednesday evening, earlier said he was ready to play if called upon.