Michael Clarke is Australia's 43rd Test captain after succeeding the injured Ricky Ponting for Monday's fifth Ashes Test in Sydney. Clarke, who has been the deputy since 2008, takes the coveted job at a time when the team is at its nadir and the 29-year-old is in a severe batting rut.

Ponting's broken left pinky not only means he may never add to his 152 Tests, but it accelerates the transition to Clarke during a summer in which his performances have indicated he is not ready for the role. He now has no choice after his appointment - and the elevation of Brad Haddin to vice-captain - was approved in a unanimous decision by Cricket Australia's board on Thursday afternoon.

"Obviously I'm honoured, it's for this Test match and hopefully we can get Punter right as soon as possible and get him back into whichever team," Clarke said at the SCG. "The sooner we can get him back into the one dayers, the better for us."

Clarke is in charge of a 12-man squad as it attempts to draw the series with England, who retained the Ashes with their innings victory in Melbourne on Wednesday. Usman Khawaja has been included to make his debut at No. 3 while Doug Bollinger was recalled to replace Ryan Harris, who suffered a stress fracture in his left ankle at the MCG.

But the major focus is on how Clarke will deal with his switch from energetic lieutenant to the man who has to juggle his own game with all the extra commitments required to run a team. He has led Australia in 18 ODIs and another 18 Twenty20s and has usually enjoyed giving the captaincy back to Ponting.

In his dream Clarke would have taken the job in peak form, but he has experienced a poor campaign against England with 148 runs at 21.14 and only one half-century. Even that came with criticism after he tweeted an apology for not walking when he was dismissed late on the penultimate day in Adelaide.

"I make no bones about it, my form has not been good enough throughout this series," he said. "I've had a couple of innings where I've felt really good but I need to get out here and make sure I get some runs on the board, and that's my focus right now. I've had the chance to captain Australia in the Twenty20 form and a handful of one-dayers as well, and I don't think it's hurt my performance. Hopefully that's the same this week."

Clarke is a modern cricketer and his metrosexual tendencies and A-list activities have created lingering questions over his suitability for the leadership. His on-field moves will now be analysed intently as he hopes for a way out of such a dire period for Australia.

Ponting's fractured finger deteriorated during the fourth Test that finished with him failing to win the Ashes for a record third time. If the urn was still up for grabs he would have pushed to play but gave into medical advice.

"I'm devastated to tell you the truth, it was the news I was dreading," Ponting said after landing in Sydney. "During the game I didn't think I'd done too much more to it." When asked if he was considering retirement he said: "I'm not thinking about it at all."

Ponting, who scored only 113 runs in the first four games, could face surgery on his finger, but is expected to be fit to guide Australia in their push to win a fourth consecutive World Cup. He had an x-ray on the final day of the Melbourne defeat and it showed the fracture had moved during the match.

"What I need right at the moment is just as much time as I possibly can to let it heal and make sure that I'm 100% right for the start of the World Cup," he said. "That's really how the decision was made, so I've just got to do everything in my power over the next little bit to look after it as well as I can."

He will see a specialist again over the next day to decide on the best way forward. "Hopefully he will commence training in the later part of the Australian summer," Alex Kountouris, the team's physiotherapist, said. "He is expected to be fully fit for the World Cup."

Ponting's Test future is less clear as Australia's next five-day engagement is currently scheduled for Sri Lanka in August, although there is a talk of a series against Bangladesh after the World Cup. He is already 36 and Australia have realised during their poor Ashes performance that they have to start rebuilding through young players.

Australia squad Shane Watson, Phillip Hughes, Usman Khawaja, Michael Clarke (capt), Michael Hussey, Steven Smith, Brad Haddin (wk), Mitchell Johnson, Peter Siddle, Ben Hilfenhaus, Doug Bollinger, Michael Beer.