Mann-Rea is back at ACT Brumbies training after an ugly clean out six weeks ago snapped his hamstring off the bone, tore his adductor and shattered his hopes of playing this year.

But the veteran rake is determined to have a positive impact this season even if he can't play, taking on a new role to help mentor the two emerging hookers who are stepping up to replace him.

Folau Faingaa and Robbie Abel boast just 26 games between them and will face perhaps their toughest test since Mann-Rea's injury when they square off against savvy Argentine Agustin Creevy at Canberra Stadium on Sunday.

Faingaa is regarded as a Wallaby in waiting, Abel has played 21 games and the Brumbies added rookie Connal McInerney to their roster to cover the loss of Mann-Rea.

Their next task is taking on Creevy, the 71-Test Argentina captain who is regarded as one of the fiercest competitors in Super Rugby.

"Now that I'm back on board I want to do some throwing sessions to help the boys tick over, we talk scrums and everything like that. I can go into a role where I do a bit of review," Mann-Rea said.

"We usually do that as a scrum unit anyway, but it's good to know what the hookers are thinking. It's different, but I'm liking it. Once you find out you're injured, you've just got to move forward.

"[Creevy] gets the Jaguares going with all the emotion and everything like that, so we'll talk about that and throw some ideas up about what works and what doesn't."

The Brumbies face a season-defining run of three games in a row in Canberra as they fight to stay in touch with Australian conference leaders the NSW Waratahs and the Melbourne Rebels.

The Brumbies haven't won back to back games this season and failed it execute in the second half against the Otago Highlanders last weekend.

They could be bolstered by the return of Henry Speight from a niggling knee problem, but the flying Fijian must complete training for the rest of the week before being cleared to play his 100th Super Rugby game.

Speight was back at training on Tuesday and would be a welcome sight for coach Dan McKellar, who is still searching for a winning mix after seven games.

Mann-Rea has already been ruled out for the rest of the Super Rugby season after a freak injury in Melbourne.

The 37-year-old was perched over a ruck when he was cleaned out by two Rebels players and his body crumpled under the strain.

He felt pain in his hamstring, but his leg went numb after a few seconds and he couldn't get off the ground.

Scans showed his hamstring tendons had been torn off the bone, as well as a torn adductor, which required in surgery and up to a six-month recovery.

"I couldn't feel my leg so I knew it wasn't good. I was trying to lift it, and it wasn't moving. It was just dead," Mann-Rea said.

"When I couldn't get up, I thought it must be bad. When I was helped off the field I couldn't even lift it to walk, it was just dragging on the ground.

"You do think about the worst [case scenario], but once you get the scans done and a recovery time frame you just rip in and get it done.

"I was on crutches and stuck in the house for the first two weeks, so that was a bit frustrating. But to be back involved now, my leg feels like it's getting better so things are progressing."

SUPER RUGBY ROUND 10

Sunday: ACT Brumbies v Argentina Jaguares at Canberra Stadium, 4.05pm. Tickets from Ticketek.