Wallabies coach Ewen McKenzie confirmed that 25-year-old Genia, regarded as one of the game's finest halfbacks, will cool his heels on the bench for the Perth match against the Pumas as penance for an indifferent start to the southern hemisphere Rugby Championship.
McKenzie, himself under pressure after three straight losses to open his tenure, cast the stunning decision as a wake-up call for his most dangerous and creative player who, in any case, would be sure to ''bounce back''.
The demotion has polarised Australia's rugby community, who have been sorely disappointed by McKenzie's failure to produce a winning team in the two months since taking over from Robbie Deans.
"When you drop your only world XV quality player to the bench, you would want a long list of very good reasons to justify it," respected rugby writer Greg Growden fumed in a column on ESPN Scrum.
"Genia's axing is baffling and dangerous, especially as Argentina is a far better team than what many in Australia think."
In dropping Genia, McKenzie has at least been true to his word, that reputations count for little in his selections.
Genia's brilliance with the Queensland Reds under his head coach McKenzie helped secure the Brisbane-based team its maiden title in the southern hemisphere's Super Rugby championship in 2011.
Barring a serious knee injury that sidelined Genia for much of last season, the pint-sized playmaker has owned the number nine jersey for the past four years, a reassuring presence for Wallabies fans and team mates alike, and a bulwark of stability in a backline seemingly always in flux.
The last time Genia played off the bench - he was rested - the Wallabies were upset on home soil by lowly Samoa in 2011.
Genia showed flashes of brilliance in the lost series to the British and Irish Lions, winning man-of-the-match in the second of three tests, despite carrying a knee injury.
He has struggled to make an impact in two opening defeats to New Zealand and Saturday's calamitous 38-12 loss to South Africa, but has hardly been alone, with team mates belted across the field.
SACRIFICIAL LAMB
As the only change to the Wallabies backline, however, Genia appears to be the sacrificial lamb.
Bob Dwyer, who coached Australia to their maiden World Cup triumph in 1991, said he had nonetheless contributed to a "pathetically slow" attack in McKenzie's new regime.
"I see absolutely below-standard performance in terms of a his role as the scrumhalf," Dwyer told Reuters.
"He can run and do all those things, he's courageous, he's a good tackler, he does get back and collect the high ball frequently but they're add-ons.
"If you can do the fundamentals of your role well, and you can do the add-ons great, but if you can't do the fundamentals well, then it doesn't matter ...
"Because the fundamentals of your position affect everyone else on the field, in this case negatively."
The promotion of White, whose international experience has consisted of three runs off the bench in the Rugby Championship, will place huge pressure on the 23-year-old and his halfback partner Quade Cooper, who failed to make an impact against the Springboks at Lang Park.
Putting aside his disappointment, Genia has given White a few pointers ahead of his maiden start.
"He's not only offered advice, he's also given me two pairs of boots," White, who wears the same size as Genia, told reporters in Perth.
White enjoyed a breakout season for Super Rugby's ACT Brumbies this year, and Dwyer suggested the speedy halfback might be able to fill Genia's shoes in a more literal sense.
"Interestingly on Saturday, the only positive attacking plays of the game by Australia came towards the end of the game was when (White) was scrumhalf," he said.
