Petaia was dazed after a tackle gone wrong in last week’s qualifying final defeat of Melbourne Rebels, ending a night that had already included an intercept try and near-miss.
But he has cleared all concussion protocols to face the Brumbies on Saturday night, who welcome their own young gun Noah Lolesio back from injury to steer the ship at No.10.
Petaia will loom large on the flank as the Reds attempt to snap a six-year losing streak in Canberra, while prop JP Smith will start ahead of Harry Hoopert.
Versatile back Jack Hardy has earned a bench spot, covering for Chris Feauai-Sautia (groin) in the only other change to Brad Thorn’s side.
The Brumbies lost to the Reds a fortnight ago in Brisbane, while the Reds have lost two games by a combined five points.
Thorn said the side would draw on the journey that began in November and included a three-month COVID-19 shutdown where they lost Wallabies lock Izack Rodda and emerging stars Isaac Lucas and Harry Hockings in a messy contract dispute.
“Grand final week, this is what it’s all about,” he said.
“We travelled around the world, we worked hard in two pre-seasons, we’ve battled through a global pandemic.
“Many of our guys in this group have come through our pathway and club rugby; they’ve thrived and have grown as men during this year.
“We’ve reconnected with our state. They believe in us and we want to make them proud this weekend, plus achieve something together as a group.”
Last week was the Reds’ first finals victory since 2011, when the side won their first and only Super Rugby title.
Joe Powell will start ahead of Wallabies halfback Nic White in the No.9 for the Brumbies in their other major change.
Reds: Jock Campbell, Jordan Petaia, Hunter Paisami, Hamish Stewart, Filipo Daugunu, James O’Connor, Tate McDermott, Harry Wilson, Fraser McReight, Liam Wright, Lukhan Salakaia-Loto, Angus Blyth, Taniela Tupou, Brandon Paenga-Amosa, JP Smith. Reserves: Josh Nasser, Harry Hoopert, Ruan Smith, Tuaina Taii Tualima, Angus Scott-Young, Moses Sorovi, Bryce Hegarty, Jack Hardy.