Josh Hazlewood is pushing to return for the Boxing Day Test as Australian selectors ponder their best fast-bowling mix.
The NSW quick has missed the last two Tests after suffering a side strain against West Indies in Perth.
Hazlewood bowled in the Gabba nets on Sunday as Australia went 1-0 up against South Africa with a six-wicket win in a Test that lasted just two days.
The 31-year-old has not declared himself a certainty for selection at the MCG but will do his best to prove his fitness.
If Hazlewood is declared fit, selectors will be forced to choose between him and cult hero Scott Boland as the third quick for the second Test against the Proteas.
Chairman of selectors George Bailey said Hazlewood was already at "90 per cent".
"He'll keep building and clearly we've got a decision to make but it's a good problem to have," Bailey said.
"A really important part of what this team is at the moment, (is) that when that opportunity is there you grab it, you come in.
"Barrel (Boland) is doing it, he's been fantastic. Hoff (Hazlewood) has obviously done it for a very long time as well."
Boland was brought in for the Adelaide Test against West Indies to replace the injured Hazlewood, having not featured for Australia since the Ashes decider in January.
The 33-year-old has continued the extraordinary start to his Test career, producing devastating spells against the Windies and at the Gabba against South Africa.
After just five Tests, Boland has taken 25 wickets at an average of 10.36.
Making a decision even more difficult is that Boland is rated as an MCG specialist after the Victorian's famous man-of-the-match performance on his Test debut last year.
Boland tore through England with 6-7 in the second innings to power Australia to a 3-0 series lead and the retaining of the Ashes on his home ground.
"He's become a specialist everywhere a little bit," Bailey said, referring to Boland.
"He was on the radar for the MCG last year because of exactly what we've seen him do."
Hazlewood has been one of Australia's most reliable red-ball bowlers for almost a decade with 217 wickets in 58 Tests.
Captain and world No-1-ranked bowler Pat Cummins clearly will not make way, while left-armer Mitchell Starc on Sunday brought up his 300th Test wicket and remains in outstanding form.
