Australia's fast bowler Mitchell Johnson (L) is congratulated by teammate David Warner (R) after dismissing Sri Lanka's batsman Angelo Mathews on the third day of the second cricket Test match at the Melbourne Cricket Ground (MCG) on December 28, 2012.   AFP PHOTO/William WEST  IMAGE RESTRICTED TO EDITORIAL USE - STRICTLY NO COMMERCIAL USE

Captaincy material ... David Warner celebrates the wicket of Angelo Mathews with Mitchell Johnson during the second Test against Sri Lanka at the MCG. Photo: AFP

DAVID WARNER could be a surprise choice as stand-in Test captain in Sydney next week in the event Michael Clarke fails to overcome the hamstring complaint that dogged him in the lead-up to the Boxing Day Test.

With vice-captain Shane Watson already ruled out of the New Year's Test against Sri Lanka, having suffered another calf strain while bowling at the MCG, there would be a leadership vacuum if Clarke pulled out at the last minute.

Warner, 26, is seen as a leader of the future and, despite his lack of captaincy experience, and having only been elevated to the Test side a year ago, he has emerged as a frontrunner in Cricket Australia's contingency planning.

Instinctive and fiercely confident, he has already been earmarked as a potential successor to Clarke in the long-term, but could have an opportunity fast-tracked for the series dead rubber if the captain's fitness lets him down.

An obvious stop-gap would be veteran Michael Hussey, in his final Test before retiring. However, his previous taste of the one-day captaincy - chiefly in a miserable pre-World Cup campaign in New Zealand in 2007 - was not an enjoyable one and he was never considered as an alternative to Watson as vice-captain when the all-rounder was appointed last year.

Warner's senior captaincy extends only to leadership of a Chairman's XI team against India last summer as well as the Sydney Thunder, but due to Test commitments he played only one game in the Big Bash League.

In the absence of Watson, he was also made vice-captain of the one-day team in the home tri-series against India and Sri Lanka, but when Clarke was subsequently forced out with injury, selectors reverted to Ricky Ponting to take the reins rather than Warner.

However, the left-hander has fans in high places in the CA structure and on Saturday was mentioned by Pat Howard, the general manager of team performance, as a possible fill-in captain, along with Ed Cowan, his opening partner.

Cowan, 30, has also been previously appointed a Chairman's XI captain, and has more experience than the younger Warner, having led the Australia A touring party to England last winter.

Any stand-in appointment would have to be signed off by the CA board. ''We have planning in place. There is no obvious answer at the moment,'' Howard said.

''We have a young team in transition but many people have captained, many people have had leadership opportunities. David Warner captained the Thunder. You had Ed Cowan take Australia A away, David Warner I think captained Chairman's XI the year before.

''At the moment Michael is the captain but we have leadership opportunities. It's one of those things that many captains say: You need to be in the job, learn, take those opportunities as the year progresses or as opportunity presents.''

National selector John Inverarity indicated last week that Hussey was regarded as a leader through his actions more than words, suggesting the 37-year-old, who has only occasionally captained Western Australia, may not come into calculations.

There was a similar debate before the Boxing Day Test when doubts over Clarke led to questions about the leadership capacity of Watson.

Howard said CA had to plan for life beyond Clarke, even though at the age of 31 and in the prime of his career, the departure of the world's leading batsman appears well beyond the horizon.

''Michael has only been in the job a year and we would be hoping to get a lot more out of him,'' Howard said. ''But there are lots of leadership opportunities in Australian cricket. We have that sort of succession planning in place.''