Matthew Hayden suffered a fractured big toe in the final one-dayer against New Zealand in Hamilton and is a doubt for the start of the World Cup.
Hayden takes time out; he carried on batting after the injury
Hayden smashed 181 not out, the best score ever by an Australian in ODIs.
But he was hit on his right boot by a yorker while helping his team to a total of 346-5 against the Kiwis.
Australian physio Alex Kountouris said: "Matthew will see a specialist in Brisbane on Wednesday when his medical management will be outlined."
Kiwi seamer Mark Gillespie was the man to do the damage, hitting the left-hander's boot as he tried to play a leg glance.
Hayden played out the rest of his innings with a runner, striking a string of sixes to pass Mark Waugh's 173 and record a new highest score by an Australian in one-day internationals.
When I got hit on the toe I knew it was broken
Hayden also had the dubious honour of setting another record - the highest score by a player on a losing team as New Zealand triumphed by one wicket in the final over.
He said: "I'm really disappointed, but the good news is we've got a bit of time, and time is the only thing that heals bone.
"It's been a pretty frustrating day.
"I must admit when I got hit on the toe I knew it was broken, it just felt ordinary. I couldn't put any weight on it at all."
The Aussies, holders of the World Cup and favourites to win this time, have been hit by poor form and injuries of late.
Pace spearhead Brett Lee (ankle) is only 50-50 for the tournament, while key all-rounder Andrew Symonds (torn bicep) is expected to miss all the group games.
Batsman Michael Clarke has hip soreness - though is not expected to miss Australia's first match on 14 March.
Australia's first game against seeded opposition comes against South Africa 10 days later.