The Brumbies' title ambitions took a significant hit in the international window; Moore needs a season-ending knee reconstruction and gritty lock Sam Carter has been ruled out for the next six weeks.

Brumbies director of rugby Laurie Fisher has called up former Waratahs, Melbourne Rebels and Western Force rake Luke Holmes as a replacement for Moore, who will have surgery in Brisbane on Monday.

Carter is aiming for a July comeback to join the Brumbies' finals bid after he courageously played almost 70 minutes of his Test debut with an ankle injury. Moore lasted just five minutes in his Wallabies captaincy debut before disaster struck and he ruptured his anterior cruciate and medial ligaments. Surgery will keep him out of action for at least eight months.

It is bad news for the Wallabies' World Cup preparations and even worse news for the Brumbies as they aim to win their last two games of the Super Rugby season to secure a spot in the play-offs.

Holmes will join the Brumbies at training this week and compete with the club's only fit hooker – Josh Mann-Rea – for selection for the remainder of the year.

"Depth, desire and character will be sorely tested, but we have to move on and you have to rely on the strength of the squad, everybody has to step up," Fisher said. "You're not going to replace like with like for Stephen Moore, a guy who's played 120-odd Super Rugby games and 92 Tests for Australia.

"We'll get a guy who will have a red-hot crack and everyone around him as to lift, but it won't be the same. It will take [us] a step backwards but we will rely on the team rallying around and getting performances out."

Moore will on Monday meet with respected surgeon Peter Myers, who has repaired the busted knees of David Pocock and Quade Cooper. Moore played all 15 Wallabies Tests last year but his injury will put a big dent in Australia's World Cup preparations less than a week after coach Ewen McKenzie named Moore as the team's new skipper.

His Brumbies back-up, Siliva Siliva, is also out for the rest of the year with knee and ankle problems.

Mann-Rea was preparing to quit rugby last year and return to work in the coalmines before signing a one-year deal to stay with the Brumbies. Holmes played for the Waratahs last year and Fisher watched the 30-year-old journeyman in Sydney club rugby on Saturday. Former Brumbies hooker Anthony Hegarty is back in Canberra, but it is understood his French club Grenoble has said no to a Super Rugby cameo.

The Brumbies play the Waratahs on June 28 before finishing the regular season against the Western Force on July 11. They need to win both games to be any chance of clinching Australia's guaranteed finals berth and one loss could ruin their play-off hopes.

Carter could be fit for the clash against the Force and the Brumbies will turn to Leon Power in his absence, while Jack Whetton and Australian under-20s second-rower Tom Staniforth will likely compete for a bench spot.

"It is really disappointing for both of them ... We're still hoping 'Carts' will be back in the next four to six weeks but without Stephen, particularly, it's going to be difficult for us," Brumbies coach Stephen Larkham said.

"We have Josh Mann-Rea and he's a really good, dogged player, so he'll step up now and we're confident he can do the job for us. It is not ideal but, as a team, we've been through a fair bit together over the last three years, so I am sure we can cope with this."

– with Georgina Robinson