Wallabies skipper Stirling Mortlock is poised to revert to outside centre as the Brumbies reshuffle their misfiring backline for Friday's big Super 14 clash with the unbeaten Waratahs.

Brumbies coach Andy Friend concedes his side has lacked penetration in attack as it battled to two last-gasp victories over the Highlanders and Crusaders then slumped to a home loss against the Western Force before their bye.

And he is poised to reshuffle his star backs in a bid to restore their free-flowing attack.

With Mortlock moving out a spot, Tyrone Smith is likely to get his first start of the season at inside centre.

Adam Ashley-Cooper is expected to go from outside centre to fullback where he played for the Wallabies last year, shifting Mark Gerrard from No.15 to the wing with either Clyde Rathbone or Francis Fainifo dropping to the bench.

Mortlock played the first three rounds at inside centre after impressing in the role on the Wallabies' spring tour, but with the exception of the first match against the Highlanders, in which he bagged two tries, he has been well contained by opposition defences.

Playing at No. 13 is a position the 76-Test veteran is much more accustomed to and one which has previously seen him rated as the best centre in the world.

Mortlock admitted on Monday he hadn't played his best rugby at inside centre in the Brumbies' three matches so far this season.

"Personally I've felt a little bit off," Mortlock said.

"I probably haven't been that comfortable in our style (of play) which is also probably a reflection of where the team has been at as well.

Mortlock said the side, which is coming off a bye last weekend, had worked hard at addressing a few structural issues in attack.

"We've been pretty direct and probably haven't had enough of an ability to change up our options.

"We haven't gelled enough. Sometimes that takes a bit of time. but also you need to have a better shape in attack and make better decisions."

"We were probably missing on all fronts."

Friend also conceded that Mortlock was probably better suited to outside centre.

"I think he's shown on the spring tour that he can play No 12, but what I've seen of him this year, he's probably more comfortable at 13," Friend said.

Mortlock at outside centre would also set up an intriguing battle with in-form Waratahs youngster Rob Horne.

While Friend would not confirm the changes, Mortlock trained at outside centre on Monday with Smith on his inside, all under the watchful eye of Wallabies coach Robbie Deans.

But Friend did admit the Brumbies attack has not been firing on all cylinders.

"The flow of our game hasn't been what it should be, so we need to have a look at what's happening with our playmakers. It's a key area that hasn't been going right."

He was confident Smith, if he is indeed given the chance on Friday, would be up to the job.

"He was tremendous last year and he's done nothing wrong this year either," Friend said.

"We're in a very fortunate position where we've got a few headaches there and a couple of good options in that No 12 jersey if we are to change it."

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