Australia captain Michael Clarke's participation in the second Test against Sri Lanka remains in the balance, while fast bowler Mitchell Starc will almost certainly be rested.

Clarke is nursing a hamstring injury sustained during the series opener in Hobart, where the hosts won by 137 runs to take a one-nil lead in the three-match affair.

Sunday saw him jog at half pace under the watchful eye of team physiotherapist Alex Kountouris at the Melbourne Cricket Ground, but the exact extent of his recovery is yet to ascertained.

"He is travelling optimistically and well. But he is 50-50 as to whether he'll be fit enough to play on Boxing Day. He is a very precious asset and I would go low risk," said national selector John Inverarity.

"He is always upbeat, he desperately wants to play. But we certainly don't want to push him especially hard in a Test for him to break down, and maybe not play for the rest of the series."

Australia have pinpointed all-rounder Shane Watson as stand-in skipper, while the left-handed Usman Khawaja will be recalled to the middle order if Clarke is absent from the clash at the MCG.

Starc, meanwhile, is likely to be replaced by fellow left-armer Mitchell Johnson or the uncapped Jackson Bird amid Australia's bid to manage the young fast bowler's workload.

"Starc will either play Melbourne or Sydney, but it would make some sense that he misses this one and plays Sydney rather than goes Hobart and then Melbourne. It's about bowling loads," added Inverarity.

"The science behind it is that they've got to build up their bowling loads so the oscillations are not very significant. If they do become reasonably significant, as they have done for Mitchell, then you enter a danger period, a high-risk period."

The second Test gets underway at the MCG on Wednesday. Sydney will host the third and final fixture.