Brumbies hooker Josh Mann-Rea has knee surgery to repair damage

Mann-Rea has had a LARS operation, which uses a synthetic rope-like structure to replace his damaged anterior cruciate ligament. The recovery time can be as few as three months compared a nine-month rehabilitation after a traditional reconstruction.

It's unclear how the decision will impact Mann-Rea's playing future as the 38-year-old weighs up whether to attempt a comeback or to finish his career.

The Brumbies have added Maile Ngauamo to their squad as the third-string hooker for the last four games of the regular season and a potential finals campaign. But Brumbies coaches told young gun Lachlan Lonergan to play for the Australian under-20s rather than staying in the capital to train.

Lonergan is in camp with the junior Wallabies as they ramp up preparations for the under-20s World Cup, which starts with a clash against Italy in Argentina on June 4.

Lonergan, the younger brother of Brumbies scrumhalf Ryan, is tipped to be a Brumbies hooker of the future. But the club opted against rushing his development by throwing him into Super Rugby too early.

"I think [Brumbies coach Dan McKellar's] best interest was for me to go and play for the under-20s," Lonergan said. "And to have a good tournament, which is what I wanted as well.

"He just said to focus on the under-20s as your primary goal for this year and so that's what I've done."

Folau Faingaa and Connal McInerney will shoulder the Brumbies' hooker duties for the rest of the year and will be the drivers of the team's key attacking weapon: the rolling maul.

Ngauamo joined the Brumbies two weeks ago on a trial and played for the Brumby Runners, with the 25-year-old impressing enough to earn a temporary Super Rugby deal.

The Brumbies will have just one training session as a full squad this week with 12 players in Brisbane for a Wallabies World Cup planning camp.

Rory Arnold, Lachlan McCaffrey and Rob Valetini are expected to be back in selection contention to play the Pretoria Bulls on Friday, but David Pocock will be monitored before a decision is made about his availability.

The Brumbies' set piece has been the anchor of their game plan in a form revival, led by their solid scrum and the success of their lineout.

The combination of James Slipper and Scott Sio has proved a success, with McKellar rotating the pair every two weeks this season in the loosehead role with Allan Alaalatoa at tighthead and Faingaa and hooker.

All four are in camp with the Wallabies and will be crucial to Australia's hopes of success at the World Cup in Japan.

"Slips has been very good, he's just doing his job well. His fitted into the club nicely and has enjoyed not being overburdened with leadership responsibility. He's an important player for us," McKellar said.

"The Wallabies will benefit and the Brumbies are benefiting, so are the individuals. Both Sio and Slipper, their attitudes have been outstanding this year. It's a tough position they're in and they will be in a good positioning coming into the back end of the season."

The Brumbies will play the Bulls, the Japan Sunwolves, the NSW Waratahs and the Queensland Reds in their final games of the regular season.

They are one point ahead of the Melbourne Rebels in the Australian conference, with the top team earning a guaranteed place in the finals.

Holding their place at the top this week will be no mean feat as they brace for a Bulls outfit sitting at the top of the South African conference.

But the Brumbies have been impressive on home soil - dropping just one game in Canberra back in February - to resurrect their season and give their hopes of hosting a final a pulse.

Their destiny is largely in their own hands with three intra-conference games to follow the Bulls clash.