Clarke injured his hamstring at training in Harare and was scratched from Monday\'s series-opener against Zimbabwe, which Australia won by 198 runs.
Australia captain Michael Clarke, sidelined with a hamstring injury, may not be fit until the "back end" of the triangular one-day tournament with Zimbabwe and South Africa, according to stand-in skipper George Bailey.
Clarke injured his hamstring at training in Harare and was scratched from Monday's series-opener against Zimbabwe, which Australia won by 198 runs. "It happens a little bit too often," Bailey said at the toss, referring to standing in for Clarke.
"Hopefully 'Pup' will be right for the back end of this series. Rest up for the first couple and then get himself right."
Australia play South Africa in Harare on Wednesday, with further matches next week before the final on September 6. Australia are likely to be very cautious about rushing Clarke back, with a two-test series against Pakistan in the United Arab Emirates to follow in October.
The team's performance without their top batsman will also have buoyed selectors, along with the straight hitting of paceman Mitchell Johnson, who blasted a six into the television commentary box window.
The shot showered Neil Manthorp and colleague Pommie Mbangwa with shards of glass.
The pair were uninjured and left-armer Johnson, who bowled Australia to test series wins over England and South Africa earlier this year, was not apologising beyond a sheepish smile and a raise of his hand when surveying the damage from out in the middle.
"I didn't see it shatter, I just saw some of the commentators brushing away a bit of glass, so it was a good thing it didn't shatter everywhere and the ball didn't go through," he said in comments published on Cricket Australia's website on Tuesday (www.cricket.com.au).
"It's something I've been working on, trying to hit straighter.
"I've been trying to hit as straight as possible instead of hitting across the line. "So I'm not going to apologise, but hopefully I didn't hurt anyone up there."