South Australia captain Travis Head will turn to one of his junior state teammates for advice ahead of his maiden Test match on home soil against India this week.

Head has all but been guaranteed a spot in Australia's XI by coach Justin Langer for the first Domain Test starting on Thursday, with one of Victorian duo Marcus Harris and Peter Handscomb set to miss out.

The decision between the left-handed Harris and the right-handed Handscomb could be influenced by Indian spin star Ravichandran Ashwin, who has been a dominant force against left-handers during his career.

Picking Harris would give Australia four left-handers in their top six, a welcome sight for Ashwin given the off-spinner averages less than 20 against lefties in Tests.

Former Australian captain Ricky Ponting told cricket.com.au last week that the Aussies should pick their best batsmen, regardless of whether they're left- or right-handed.

And Head, another left-hander, said the hundred SA teammate Harry Nielsen scored against India in their tour match in Sydney last week proves that lefties can thrive against the dangerous Ashwin.

"Harry played well against him yesterday so when he gets home off the plane I'll have a word to him," Head said.

"He's a world-class bowler, but I think we've got some world-class batters as well. So I think it'll be a good contest."

Ashwin finished with figures of 2-122 against an inexperienced CA XI at the SCG, with left-handers Nielsen (100 from 170 balls) and D'Arcy Short (74 from 91) handling him well.

Ashwin is a destructive bowler at home, but his record abroad and particularly in Australia means the hosts would be loath to put too much focus on him when it comes to settling on their final XI.

The 32-year-old has 21 wickets at 55 from six Tests in Australia, compared to a career bowling average of 25, and his strike-rate almost doubles on Australian soil compared to when he plays at home. He took 12 wickets in three Tests in Australia four years ago as left-handers David Warner and Chris Rogers both averaged more than 50 for the series.

Ponting says the left-handedness of Harris should not be a factor in the minds of selectors.

"They've just got to pick their best batting line-up, simple as that," he told cricket.com.au.

"Don't worry if they're all left handed or if they're all right handed."

Coach Justin Langer has said Head will "definitely" play the first Test, but the 24-year-old is trying to contain his excitement ahead of a possible maiden Test at his home ground.

"I'm not sure, we'll find out," he said when asked if he's a lock in the XI.

"We'll get through the next couple of days of training, train well, prepare well and prepare to play. I feel ready to go and hopefully I'll get the nod.

"Our bowlers … they'll test us out in the next three days, which will be good.

"Then you can walk out in the middle knowing you've prepared well and are ready to go. If I can get through those guys I think I could get through anyone in the world."