But starting on a minimum wage contract, living at home with his parents and juggling part-time work pournig beers and collecting glasses at pubs, the Brumbies are backing Staniforth to add 19-year-old mongrel and excitement to their forward pack.

Staniforth, the 196 centimetre, 113 kilogram Australian under-20s representative, will rocket out of obscurity to join the Brumbies on a supplementary contract ahead of their blockbuster Australian conference derby with the Queensland Reds on Friday night.

Lock Sam Carter will miss at least a month of rugby after injuring his knee in the 26-9 win against the Auckland Blues. He will meet with surgeons on Monday.

It means Staniforth will compete with Jack Whetton and Wests' Dave McKern to compete for a chance to take on the Reds' Test duo James Horwill and Rob Simmons at Suncorp Stadium.

Supplementary contracts are for a minimum of two weeks and maximum of 12 months, with Staniforth set to earn a modest training wage and match fees.

"We're hoping [Carter's injury] is shorter term than long. He's been great for us and right up there with the best locks in the competition," said Brumbies director of rugby Laurie Fisher.

"We've only got Scott Fardy and Jack Whetton as locks in the squad. Tommy has trained with us on and off over the last 18 months. He's had some outstanding development, he has an uncompromising attitude.

"For a guy who's young, he's got a good old head on his shoulders."

The Brumbies hope to regain hooker Stephen Moore and prop Scott Sio to take on the Reds but have no back-up locks, with Carter and Leon Power injured, while flanker recruit Tom McVerry is also ready to play.

Jesse Mogg (hamstring), Matt Toomua (knee) and Robbie Coleman (cork) were also carrying niggling injuries, but all are expected to play against the Reds.

Former Canberra Grammar student Staniforth is one of a host of the capital's best club players trying to impress Brumbies coaches.

Fisher said the Brumbies were keeping a close eye on Canberra's premier division to see who can make the step up to Super Rugby or the new National Rugby Championships, which start in August.

Staniforth is highly regarded at the Brumbies, earning praise from Wallabies skippers David Pocock and Ben Mowen.

The cousin of former Wallabies winger Scott Staniforth, the towering teenager has bulked up from 105 kilograms to 113 kilograms this year, has been described as having "tree trunk legs" and is tipped to be the Australian under-20s captain at the world championship later this year.

Staniforth was named player of the national under-20s championship in Canberra two weeks ago.

The Brumbies lost to Queensland in the opening round of the season and will be desperate to beat the Reds on their home turf for the first time since 2011.

"It's huge, massive. We've already touched on it as a group. In the last three years we haven't gone to Suncorp and got a win yet," said Brumbies captain Ben Mowen.

"Round one they had our measure, they're an extremely challenging side to play. They're a huge threat to being the top side in the Australian conference. It's a great opportunity for us to test ourselves, we're already excited by that."