The likelihood is that the vacancy will be at the top of the order but there may also be a spot for another reserve batter in the era of concussion substitutes. Here's a look at the runners and riders.

"It's not like it's going to be the first time I've ever played for Australia A before a Test series," he said last week. "There's obviously always a bit of attention around those games. Pressure wise, I'm not going to be trying to put the same pressure on myself as I had before. It will just be a great opportunity."

He is the 19-year-old new kid on the block and generating plenty of excitement. Konstas has been compared to Ricky Ponting and joined him as a teenager to make twin hundreds in the Sheffield Shield. Bailey was careful to temper expectations and it would be a very rapid rise - and against the grain for Australian men's cricket - if he was catapulted into the Test squad in a few weeks.

"He's in the mix as are plenty of others," Bailey said. "I certainly don't want to single him out. Think the consistency of Cam Bancroft over a number of years, the consistency of Marcus Harris over a number of years, they've both had a look at Test cricket as well, so don't think there's a need at this stage to put any undue pressure or expectation on Sam."

But the opportunity is there for him to make the selectors think hard. He will face Scott Boland at the MCG from Sunday before what will likely be a strong India A side. Another couple hundreds against those attacks and the momentum could be unstoppable.

Renshaw was the reserve batter against West Indies and New Zealand earlier this year but has been overlooked for the Australia A squad. He made 6 and 15 in the opening round of Sheffield Shield against Western Australia. However, Bailey said that doesn't mean the selectors have moved on from him, while also referencing a couple of other experienced domestic players who have had a taste of Test cricket.

"We still really like Matt's ability to play," Bailey said. "As far as Australia A selection goes, part of the process around that is trying to identify opportunities that may come around in the short term but also making sure we do keep an eye on developing opportunities for those players who may become important in different roles in the future as well. Whilst there's an Australia A squad there, I think Matt Renshaw, Peter Handscomb, Nic Maddinson, as three examples, are guys who we'll continue to watch really closely in Shield cricket."

The other aspect is that even after the initial Test squad is named there will be three more rounds of Shield before the BBL for players to impress should back-up be needed during the series.

"I'm definitely confident in my game at the moment and if I were to get an opportunity I think I would be ready," he said on Thursday. "But all I can do is to continue to focus on what I can control and that's preparing well for South Australia and hopefully winning games for my state."

Webster, the Tasmania allrounder, has numbers that speak for themselves over the last two seasons. With the bat he has averaged 53.12 in the Sheffield Shield - including an opening-round hundred last week - while has taken 66 wickets with a combination of brisk medium pace and offspin. Add in bucket hands at slip and he's an ultimate allrounder. The Australia A series is a chance for him to do it a level up and success there will keep him in the frame should there be a need for another allrounder down the track. His versatility could also put him in consideration for the Sri Lanka tour early next year.

Alongside Webster, Hardie is the other emerging allrounder and had an excellent limited-overs tour of England, especially with the ball whereas overall his batting is his primary suit. Bailey told cricket.com.au that there had been consideration to trying to get Hardie one of the Australia A matches but with Green's injury it was felt he would be needed through the ODI and T20I matches against Pakistan. There may be an opportunity for him to bat slightly higher in the order in the ODIs. He is due to return to Shield action at the weekend where he will be expected to slot in as part Western Australia's top order. Hardie hasn't scored a Shield century since his unbeaten 174 in 2021-22 final although did make one for Australia A in New Zealand a few weeks after that. In the last two seasons for WA he has averaged 31.45 so he may need a big season to push his case.

And what about the bowlers?

There is probably less mystery about who will be the back-up to the big three. It appears unlikely that Lance Morris will be in consideration amid his managed return from back problems (and a more recent thigh niggle) which leaves Boland and Michael Neser leading the way. Sean Abbott was part of the squad when India last toured in 2020-21 and, along with Neser, is someone who would bring some extra batting depth.