Brumbies skipper Stirling Mortlock has been ruled out of Saturday night's Super 14 crunch match against the high-flying Sharks at Canberra Stadium.

Mortlock's absence is the only change to the side which upset the Blues 16-11 last weekend when the powerful centre sustained an accidental knee to the head.

Fellow Wallabies incumbent Adam Ashley-Cooper shifts to outside centre while Francis Fainifo has been promoted from the bench onto the left wing and flanker George Smith takes back the captaincy.

Among the Brumbies' best against the Blues, Ashley-Cooper will play in his third position in as many weeks back from injury having started at fullback against the Chiefs.

The highly-rated 23-year-old is looking forward to running on in his preferred position.

"It's disappointing to lose Stirlo," he said.

"In saying that, we've played without him through the first half of the competition, so this isn't a new obstacle for us.

"We realise what a challenge we're in for on Saturday. The Sharks have quality players across the field from one through to 22 and if we don't turn up to play then they will make us pay."

The Brumbies bench has also received a boost with the inclusion of talented No.8 Stephen Hoiles, who returns from a cheek injury suffered against the Chiefs a fortnight ago.

Hoiles joins an extended reserves list with prop Ben Alexander and centre Sanualio Afeaki included on the eight-man bench.

Brumbies: Mark Gerrard, Peter Playford, Adam Ashley-Cooper, Tyrone Smith, Francis Fainifo, Christian Lealiifano, Patrick Phibbs; Julian Salvi, George Smith (capt), Mitchell Chapman, Mark Chisholm, Alister Campbell, Guy Shepherdson, Saia Faingaa, Nic Henderson. Res: John Ulugia, Salesi Ma'afu, Peter Kimlin, Stephen Hoiles, Josh Holmes, Matt Toomua, Sanualio Afeaki, Ben Alexander (one to be omitted).

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