That reduced training loads due to concerns about the impact on players, most of whom have limited experience of training on 4G pitches.

“They [McReight and Frost] both played 80 minutes, and they had accumulated quite a bit of fatigue and a few knocks,” Schmidt said. “So, they’re OK, but our plan for the week was to get up here and train Tuesday, Wednesday, Friday.

“As it happened, we’ve been quite limited in what we’ve done. Maybe they could have been all right by now, but we just thought we’ve got a confidence in the squad and it was important to demonstrate that.”

The Scotland Rugby Union gave the Wallabies rare access to Murrayfield, which has undersurface heating, to train on Friday.

“They let us onto Murrayfield so that we could train and it meant that we could actually get a session on the grass,” Schmidt said. “And hopefully, you know, that just sharpens the boys ready for Sunday.

“We would certainly go lighter and less duration, less density [on 4G pitches]. We wouldn’t do as much in a short space of time, which is fine. At this end of the season, maybe it’s not a bad thing.”

Schmidt said the decision to back Potter, Tizzano and even Zane Nonggorr over Taniela Tupou – who trained fully on Friday after a knee injury – was a deliberate strategy to show faith in the squad and build valuable depth.

“We’re trying to build a squad going forward and that’s part of it, and it helps us sustain a competitive element to our squad,” Schmidt said.

“Because I think if you’re not internally competitive it’s hard to be externally competitive. But at the same time, there’s a lot of continuity as well.”

Tizzano makes his return to the side for the first time since his impressive debut, and a run of four Tests, when McReight was injured during the Rugby Championship.

“He made 66 out of 67 tackles, and he got half a dozen turnovers and added value,” Schmidt said.

“So, again, when somebody gets an opportunity and takes it – I’m not saying that Fraser didn’t come straight back in for the Bledisloe Cup games and play really well, and he’s played well so far – but I think it’s a vote of confidence for how Carlo went.”

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Potter will become the 18th player to make his Test debut this year, which is the most for the Wallabies since 1920 and 1928, when Australian rugby was still finding its feet again. All Australian rugby competitions stopped during World War I, so players could serve in the armed forces.

Schmidt pointed to Potter’s familiarity with UK rugby and conditions. The Melbourne-raised 26-year-old played three seasons for the Leicester Tigers before returning to Perth to try and make a Wallabies squad.

“Harry’s played a lot in this hemisphere and quite successfully,” he said. “It’s a good opportunity to give Harry his first start. Max was exactly like the other two boys; we’re trying to let him heal a bit.”

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