Melbourne, Nov.22 Former star players have questioned Michael Clarke's capacity to ascend to the Test captaincy and believe Ricky Ponting must lead Australia to England for Ashes revenge in 2013.

Former Australian vice-captain Ian Healy said the 28-year-old had yet to prove he was durable enough to succeed Ponting.

Clarke's worrying back problem, coupled with Ponting's fierce ambition to plot England's demise on foreign soil in four years, could prove insurmountable hurdles to "Pup" becoming top dog.

Viewed as Ponting's natural successor after being named deputy for the West Indies tour in 2008, Clarke is in danger of becoming the Peter Costello of Australian cricket.

Clarke will be 32 when Australia embarks on its next tour of England.

"Michael Clarke hasn't convinced me that he's durable enough to be captain," Fox Sports quoted Healy, as saying.

"Clarkey has to get on the field - that's an issue he has to address before we ask who should replace Ricky. Michael has missed a lot of games lately and that's not a good sign. He should not come into the equation at all until Ricky Ponting wants a succession plan," he added.

Ponting, who turns 35 next month, told ABC that he will take every possible chance to give himself an opportunity to be in England in 2013.

And therein lies the conundrum for Clarke. Since his masterful 151 on debut against India in 2004, Clarke has been Australian cricket's wonder boy earmarked for the ultimate responsibility.

He said the right things off the field; delivered the goods on it. But the longer Ponting thrives, and endures, the greater the prospect of Clarke's Test captaincy dreams fading away.

Ponting was 29 when he inherited the Test captaincy from Steve Waugh in 2004. Clarke, it seems, will be asked to wait a little longer.

Former Test wicketkeeper Steve Rixon, an outspoken critic of Ponting's captaincy, believes the handover has to take place within the next 12 months.

"I don't want to see Clarke coming into the role as a 32-year-old. No one will want that," he said.

Former Test captain Kim Hughes claimed Ponting would finish his career as a great leader.

"Ricky Ponting's efforts in India last month is some of the best leadership I've seen in decades," Hughes said.

"He was simply magnificent. To triumph in India, when we were 2-1 down, with all the injuries, his leadership was outstanding," he added. (ANI)