A pair of "frustrating" performances aren't cause for panic stations in Canberra, with Brumbies assistant coach Peter Hewat calling for a lift in enthusiasm to combat ACT's slow start to the season.

The Brumbies were beaten at their own game in a slog fest against the Reds before being blown off the park in the second half against the Rebels.

The common theme through both matches has been a dour attack, with the backs yet to be let loose.

Hewat told reporters in Canberra on Tuesday that would change come Saturday night.

"I think we were down on energy against the Reds and probably again on Friday night," Hewat said. "I think we started the game well but we lost a little bit of spark through the last 20 of both halves, really.

"Whether that's fatigue or the travel we've done, we've got some things there that we are working on and adjusting.

"That's something that we are looking to get into our game - some enthusiasm and some spark - it's a mindset thing."

ACT's solitary win through their first three starts was an unconvincing one against the lowly Sunwolves in Tokyo but having spent the best part of a month on the road, the Brumbies now return home to host the Sharks on home soil.

While Hewat stopped short of using the travel as an excuse for their slow start, he did point to the return to GIO Stadium as a major positive.

"It's really pleasing to be home this week, sleeping in our own beds and getting a full week of training and then really having a good game on Saturday night against the Sharks," he said.

"But that's been no excuse in terms of our performances.

"We have shown in patches what we are looking to do but we need to now just get a more consistent performance and getting those passages of play over 80 minutes of rugby."

Hewat also indicated his side may look to the posts should they find themselves in a similar situation to the clash with the Rebels, where they repeatedly turned down points in the first 20 minutes in favour of a rolling maul close to the Melbourne line.

While they did eventually reap rewards through a try to Chance Peni, Hewat said that was one part of their play which was reviewed with particular interest this week.

"We obviously had a plan on Friday night to attack their maul early and that didn't work out," he said.

"We've sat down this week and looked at things technically.

"Looking forward we may take points but again, that's definitely not why we lost the game on Friday night."

Hooker Josh Mann-Rea is expected to be absent from the team that is named on Thursday, though the severity of his hamstring injury is not yet known.

Co-captain Sam Carter trained on Tuesday having missed the majority of the Rebels clash with a head knock but a decision as to whether he will line up on Saturday will be made closer to game day.

The Brumbies face the Sharks at GIO Stadium on Saturday night, kicking off at 7:45pm AEDT, broadcast LIVE on FOX SPORTS and RUGBY.com.au radio.