Brumbies driven by Pocock's energy

The returning David Pocock has given the Brumbies an extra kick of energy ahead of Saturday's potentially season-defining battle with reigning Super Rugby champions the Highlanders.

Pocock is back from a two-game suspension just in time for the trip across the Tasman - with coach Stephen Larkham crediting the Wallabies superstar as the driving force behind a change in attitude following last week's 40-14 drubbing at the hands of the Crusaders.

Larkham suggested after his side's biggest ever loss at GIO Stadium that the performance stemmed from errors at training.

But it's been a different story this week during sessions in Canberra on Tuesday, and in Queenstown on Thursday and Friday in the build-up to the match in Invercargill.

"There was superb energy and execution," Larkham told AAP.

"It's been a different week, a shorter week, but the motivation's high."

And that has a lot to do with outside flanker Pocock, who scored a first-half hat-trick the last time the Brumbies played the Highlanders in 2015.

"He's driving the energy in the team at the moment," Larkham added.

"Whenever you get a world-class player back in the team it's beneficial.

"He's full of enthusiasm and ready to get out there and play."

The addition of Pocock is just one of several changes Larkham has made to the Brumbies' line-up.

Injuries to co-captain Stephen Moore (calf) and winger Joe Tomane (knee) have handed Josh Mann-Rea and Nigel Ah Wong spots in the starting side, while Wallabies props Scott Sio and Ben Alexander have been rotated out.

Sio and Rory Arnold have been moved to the bench and Ben Alexander rested, with Ruan Smith, Allan Alaalatoa and Tom Staniforth all promoted.

"We'd always planned to try and get some rotation, particularly through the forwards, in this block at some stage," Larkham said.

"The guys who have been given an opportunity this week are ready to step up. They've done a fantastic job coming off the bench and they should be fine."

The Brumbies, who have slipped to second in the Australian conference behind the Melbourne Rebels and ninth overall, have lost three of their past five matches - all by 20 points or more.

They have the wood over the Highlanders, winning seven of their past eight clashes, but Larkham knows the defending champions are a dangerous outfit.

Their kicking game, particularly, was tactical and clever - led by All Blacks Ben Smith, Aaron Smith and Lima Sopoaga.