Fairfax Media can also reveal former coalminer Mann-Rea, 33, is poised to sign a new one-year deal with the Brumbies to extend his career for at least one more season.

Mann-Rea has been given the mammoth task of stepping into Wallabies captain Stephen Moore's shoes to prop up the Brumbies' front row and lineout for their qualifier clash and grand final rematch against the Waikato Chiefs on Saturday night.

It will be just the second starting XV appearance in Mann-Rea's career, which has taken him from Australian junior sides to the coalmines after wasting opportunities to Japan, the NSW Waratahs and now to the Brumbies.

"Two years ago there's no way I thought I would be here,'' Mann-Rea said. ''After Japan for a while I thought footy was over."

"I got a lifeline to the Waratahs when [hooker Damien] Fitzpatrick got injured, then I broke my thumb and I thought it was gone again.

"But I got a lifeline from the Brumbies and now I'm getting a second chance to play in a Super Rugby finals match. Not many guys get a second chance at my age."

Mann-Rea has been thrust into the Super Rugby deep end with Moore suffering a season-ending knee injury and back-up Siliva Siliva having knee and ankle operations.

Despite being the second oldest player in the Brumbies' squad, he is the most inexperienced with nine games under his belt.

But the hard-working front-rower – known as Bongo to his mates – has refused to give in despite plenty of setbacks.

Just three weeks ago his season appeared over when he tore his hamstring. Last year he was ready to retire when he ruptured the anterior cruciate ligament in his knee, but he fought back to play just three months later.

Mann-Rea trained with Moore in the Queensland Academy and earned a spot in the Australian junior team alongside future Wallabies Matt Giteau and Mark Gerrard.

But instead of following their path, Mann-Rea found his career at a crossroads and he went to work in the coalmines at Wollongong before getting an offer from Japan.

And unfazed by the task at hand, Mann-Rea says he will not be a weak link in the Brumbies' armour.

"I've got two Wallabies props beside me and a lot of Wallabies in the forward pack; we stick by each other," Mann-Rea said.

"I just do what I do, and hopefully that's enough to get us through the game. You can't carry passengers in the final, we want to play upbeat rugby."

Mann-Rea is in the final stages of negotiating a new deal to stay with the Brumbies next year to team up with Moore and Siliva.

"It's always good to know where you're going to be the next year, especially with my wife and two kids – they love Canberra," Mann-Rea said.

His performance against the Western Force last weekend earned high praise from Wallabies prop Ben Alexander, Moore and director of rugby Laurie Fisher.

"He was terrific, he made 14 tackles and his set piece was sound," Moore said. "That will be important again on Saturday.

''You don't see older guys getting opportunities in Australian rugby; it's more common in the northern hemisphere.

"Bongo is a great example of someone who has been around and now gets the experience."