Recalls made as Australia name Sydney Test squad
The pair of players provide remedy to an injury-ravaged playing group, with all-rounder Cameron Green and quick Mitchell Starc both suffering fractured fingers on their respective bowling hands.
A spot in the XI would end a wait of over four years for Renshaw, who coincidentally last played Test cricket against the Proteas in Australia's infamous 2018 tour. Agar meanwhile last appeared in a Baggy Green cap in September 2017, in a seven-wicket victory over Bangladesh in Chattogram.
Agar's inclusion hints the Aussies are expecting a characteristically dry Sydney Cricket Ground surface, with Australian selector Tony Dodemaide citing the left-hander's aptitude with the bat could well contribute to the home side's effort.
“Ashton offers a second spin option should the Sydney pitch be conducive to turn, as it has done in the past.
"He also brings a solid batting component."
Renshaw meanwhile has pressed his case through strong Sheffield Shield form, as well as runs against the touring West Indies team for the Prime Minister's XI earlier in the summer.
The 26-year-old has played 11 Tests, with his only century at the SCG, against Pakistan when he was just 20 years old.
Dodemaide said Renshaw's selection is a nod of his ability to either slot in at the top of the order, or perhaps fulfilling a role further down.
“Matthew is included as a versatile batting option who is in good form, including an unbeaten century in the recent PM’s XI tour match against the West Indies."
Selectors were coy on the make-up of the fast-bowling group however, with young Lance Morris lingering to potentially making his debut, even with Josh Hazlewood recovering from a side strain.
“In terms of fast bowlers, it’s a blessing to have Josh returning while Lance offers a genuine point of difference with his raw pace and skill," Dodemaide added.
“This squad will cover all bases for when we get to Sydney and assess the conditions closer to the Test match.”
The third Test begins on January 4, with a win sealing Australia's spot in the 2023 World Test Championship final.
Australia squad: Pat Cummins (c), Scott Boland, Alex Carey, Cameron Green, Marcus Harris, Josh Hazlewood, Travis Head, Usman Khawaja, Marnus Labuschagne, Lance Morris, Nathan Lyon, Steve Smith, Mitchell Starc, David Warner