But captain Stephen Moore is confident his team can rally to save their season and be a championship contender.

The Brumbies arrived back in Canberra on Monday night still riding high after beating the Johannesburg Lions 30-20 at the weekend.

They finished with six points from two games – a bonus-point win and a bonus-point defeat – to keep them at the top of the Australian conference for at least one more week.

But their poor discipline is the No.1 area of concern as they fight the NSW Waratahs for Australia's guaranteed finals berth.

Referees pinned the Brumbies 19 times for infringements against the Cape Town Stormers and 13 times against the Lions.

The majority of penalties came from the wobbly scrum, but the Brumbies also missed 25 tackles against the Lions and were forced to scramble to secure a morale-boosting victory.

"We've been trying to keep positive for the last month. We haven't had the results but our preparation has been good," Moore said.

"I want the guys to enjoy the time off and use it to freshen up and arrive for the last three games knowing we'll give it everything.

"We've got a lot ahead of us, in the next month if we're good enough, we'll make the finals."

The team is expected to be bolstered by the return of Wallabies prop Scott Sio for the clash against the Bulls while playmaker Matt Toomua will have a scan on his injured ankle on Tuesday.

The Brumbies' scrum was put under the blowtorch by two of the best set-piece teams in the competition. It crumbled against the Stormers, but started to restore dented pride against the Lions.

Sio's return will be a huge boost to the forward pack as they prepare for another brutal battle against a South African team when they play the Pretoria Bulls on May 29.

"We adapted on the run in the scrum against the Lions and I was really happy with the way the guys finished it," Moore said.

"We finished on a good note and we need to pick it up from there for the next game."

The Waratahs can knock the Brumbies out of the top six if they beat the Canterbury Crusaders in a grand final rematch next weekend.

The Brumbies have a bye and need the Crusaders to get championship revenge to hold a ladder advantage in the last three weeks of the regular season.

"We know what to expect against the Bulls," coach Stephen Larkham said. "We're not looking at where we're sitting on the table, we're just focusing on making sure our details are right."

Larkham will wait until later in the week before deciding which players will suit up for Canberra club rugby duty next weekend.

Robbie Coleman looms as the man most likely to fill in for Toomua at inside-centre if the Wallabies playmaker is ruled out with another ankle problem.

"I thought Robbie played quite well when he came on to replace [Toomua]," Larkham said. "We'll reassess when we get back [into the office]. There's no doubt about [Sio] coming back into the team; he's on track.

"We'd like the guys to freshen up this week. We've had four games that we've lost by three points or less. We knew we were on the right track.

"I thought the effort and energy has been exactly where it needed to be; the bond in the group is really tight at the moment."

Toomua is hopeful of being fit to play the Bulls and said the back line was starting to click after some rusty performances.

"We've still got a way to go. It's never fixed within a week," Toomua said of the Brumbies' performance. "Teams get used to how you play; you've got to constantly change things and evolve. But it was a step in the right direction."