Maybe you are thinking of a post of
Taipan168 that I can't find now. It had a starting team and reserves, but maybe it was just his idea of it as I don't recall seeing it anywhere else. Usually they don't announce the starting team before they start their training.
The first thing I do on match day is to look at the programme to see who is starting, though sometimes the info is leaked out during training.
Maybe things have changed or my memory fails me, but if not: they would have picked a notional starting team and reserves that balanced the matchday squad.
But there is always a gap between the Oz Championships from which the teams are selected and the matches against the visiting teams; so there would be no profit in announcing early who is going to run on.
They may have noticed a drop-off in form (or vice-versa) in some players—and anyway wanted a bit of competition at training to keep the lads on their toes.
Injuries could require a recalibration within a 23 so that a lad who was notionally starting could be relegated to the bench because of combinations—though usually it would be the other way around.
Back in the day, they didn't pick two lots of 23; they used to pick a starting XV and a 23 for the A team. Then the best from the As' game against the visiting team would be on the bench for the main game a few days later.
It seemed to work—so long as they had time to print the programmes for the main game.
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