Pocock out of Chiefs clash after head knock

Sydney - Star flanker David Pocock has failed to recover from a head knock and was on Thursday ruled out of the Brumbies' Super Rugby clash with the Chiefs.

No chances are being taken over the health of the key Wallaby in a Rugby World Cup year after he was forced from the field after just five minutes in the Brumbies opening-round defeat to the Melbourne Rebels.

He failed a head injury assessment at the time and coach Dan McKellar said his return needed to be carefully managed after a third concussion in less than 12 months.

"We are just following medical protocols there and making sure we do what's best for him," McKellar told reporters ahead of Saturday's match in Canberra.

"It's an important year for him and all going well he'll be available for the (round three) Hurricanes game.

"Poey is obviously a massive loss," he added.

Toni Pulu (eye socket) and Henry Speight (hip) were also ruled out with injury.

Tom Cusack replaces Pocock in the back row, with wingers Andy Muirhead and Chance Peni in for Pulu and Speight.

McKellar has stuck with James Slipper, who served a two-month drug ban last year, as his loosehead prop ahead of Wallabies No 1 Scott Sio, who will come off the bench.

Saturday's clash in Canberra is scheduled for 10:45 (SA time).

Teams:

Brumbies

15 Tom Banks, 14 Chance Peni, 13 Tevita Kuridrani, 12 Irae Simone, 11 Andy Muirhead, 10 Christian Lealiifano (captain), 9 Joe Powell, 8 Lachlan McCaffrey, 7 Tom Cusack, 6 Rob Valetini, 5 Sam Carter, 4 Rory Arnold, 3 Allan Alaalatoa, 2 Folau Fainga’a, 1 James Slipper

Subs: 16 Josh Mann-Rea, 17 Scott Sio, 18 Leslie Leuluaialii-Makin, 19 Blake Enever, 20 Peter Samu, 21 Matt Lucas, 22 Wharenui Hawera, 23 Tom Wright

Chiefs

15 Shaun Stevenson, 14 Ataata Moeakiola, 13 Tumua Manu, 12 Anton Lienert-Brown, 11 Etene Nanai-Seturo, 10 Damian McKenzie, 9 Te Toiroa Tahuriorangi, 8 Tyler Ardron, 7 Lachlan Boshier, 6 Mitchell Brown, 5 Michael Allardice, 4 Brodie Retallick (captain), 3 Nepo Laulala, 2 Nathan Harris, 1 Aidan Ross

Substitutes: 16 Samisoni Taukei’aho, 17 Tevita Mafileo, 18 Sefo Kautai, 19 Taleni Seu, 20 Mitchell Karpik, 21 Jonathan Taumateine, 22 Orbyn Leger, 23 Bailyn Sullivan