Australia captain Michael Clarke put himself through a tough fitness Test on Tuesday but has not decided whether he will lead his side in Wednesday's second cricket Test against Sri Lanka.
Clarke suffered a hamstring injury during last week's 137-run win by Australia in the first Test and has made steady improvement in recent days, including batting and fielding sessions at the Melbourne Cricket Ground on Christmas Day.
"It's improving every day ... but a decision can't be made today," Clarke said. "I'm still pretty positive I'll be right for tomorrow. I haven't run at a 100 percent but I've certainly built up over the last three days."
Batsman Usman Khawaja, who has been out of the Australia side for a year, is on standby for Clarke.
Paceman Jackson Bird will make his debut in place of injured quick Ben Hilfenhaus, while Mitchell Starc has been rested and his fellow left-armer Mitchell Johnson returns to the lineup.
Meanwhile, Sri Lanka captain Mahela Jayawardene said he is expecting some repercussions at the MCG amid ongoing tensions over ball-tampering accusations made against Australia's Peter Siddle.
Sri Lanka made an unofficial complaint to International Cricket Council match referee Chris Broad during the first Test in Hobart last week. Although the allegation was dismissed, Siddle said later he was upset because his name had been mentioned critically in social media following the complaint.
The last time Sri Lanka played a Test at the MCG in 1995, spinner Muttiah Muralitharan was no-balled seven times in three overs for throwing.
"We have been through a lot of hostile things in the past ... 1995 was one and even after that," Jayawardene said. "I don't think that fazes our team. It might give us something extra.
"You have to remember there will be a good partisan Sri Lankan crowd, as well, so that will be good. It might go against him (Siddle). We can't control what happens out there. A lot of the younger guys probably won't even understand what the crowd's going to tell them."
Sri Lanka's best Test results in Australia have been two draws. The team has been defeated nine times.
But the Sri Lankans still believe a win during the current three-Test series is possible.
"I've been a part of a lot of good teams and good performances, so if we do that, it won't be for me personally but for the entire team and for the entire country," Jayawardene said. "It would be something good and it would be for the next generation to look at."
Australia team (possible): Michael Clarke (captain), Ed Cowan, David Warner, Phil Hughes, Shane Watson, Mike Hussey, Matthew Wade, Mitchell Johnson, Peter Siddle, Nathan Lyon, Jackson Bird. (Usman Khawaja is on standby for Clarke).
Sri Lanka: to be named.