Konstas will become the fourth-youngest Australian to make his Test debut at 19 years and 85 days on Boxing Day against India, with only Ian Craig, current captain Pat Cummins, and Tom Garrett making their debuts at a younger age.

"We said from the get go, when leading into the summer, that we wouldn't shy away, and age was no barrier," McDonald said. "And what he's shown is an array of shots, the ability to put pressure back on to opponents and he gets his opportunity. We're really excited for him."

Head had a short hit on Tuesday in the nets after doing some running and some fielding on the outfield, having not done anything at Monday's optional session.

"Has he got some things to work through? Yeah, he has," McDonald said. "So that's what you would have seen. There's no concern at the moment. Has he been officially ticked off? I'm not sure. I didn't see the sort of back-end of his training session there, but I'm pretty confident he'll play.

"I think he looked good with the bat in hand so obviously skills are in good order. It'll just be basically what risk is associated with that. He had a small strain to the quad. But no concerns from my end. He's been able to be running, so I think he'll be fully functional come the game time."

Head did have a lengthy discussion with McDonald and Australia's physio Nick Jones shortly after his hit in the nets but the coach downplayed its significance.

"It was more around his fielding position and what he was capable of there," McDonald said. "Clearly coming off a strain he's got that, obviously the demands of bat pad.

"So that's all that was about. And my question to Nick Jones was just around what he's got to do to finish off the session, so I was across it beforehand, or just making sure nothing had changed during the session, and then we just started to speak about India, what they might do. So it was nothing really that specific."

"If we didn't pick Scotty here, and I'm not allowed to declare the team, because that's Pat's job tomorrow, but I don't think I'm coming to the ground Boxing Day if Scotty is not the XI. So you can go with that as well," McDonald said.

McDonald stopped short of confirming if there would be any more changes. It appears unlikely given Mitchell Marsh is fully fit. He had one of his longest bowling spells of the summer in the nets on Tuesday and looked to be moving well having overcome the back issues that plagued him since he suffered spasms in the fourth ODI against England at Lord's back in September.

"Just to clear up, Mitch Marsh is fully fit and available to bowl," McDonald said. "I know that he only bowled two overs last game, and people were speculating around that, but that was more because of the weather interventions, and we're able to keep our fast bowlers fresh, albeit we only had two out of the three operating. But he's ready to go, and I think he'll play a role in this Test match with the ball more so than the previous ones."

McDonald was pleased to have him in the squad alongside the other spare fast bowler Sean Abbott and feels he could be needed in Sydney if the Melbourne Test were to go five days and Australia's bowlers were stretched. However, McDonald thought that was unlikely given the surface and the lighter loads that both Cummins and Mitchell Starc have had across the series so far.

"Jhye's been impressive," McDonald said. "Clearly had a setback in the Shield game with the shoulder. Every week that goes on, people are confident that it lessens the risk. And what we saw in the nets today is a highly-skilled player, and he's getting somewhere near his best, which is exciting for us.

"Carrying the two extra quicks in the squad with the short turnaround, I think that's real. If this game becomes long into a short turnaround, then you've got to make some decisions. Our frontline quicks, in terms of Starcy and Paddy, are well placed. Probably, less load than we would have imagined after three Test matches so does that give them opportunity to back up from Test four to Test five? I'd say that's highly likely."