The defender has experienced complications relating to his knee reconstruction surgery last April in which a graft was taken from his hamstring.
«Unfortunately, Hamish is having some issues with the graft site from the ACL operation he had last season,» Power medical boss Tim O’Leary said.
«He is working through the appropriate progressions to return to full fitness over the next month or so.»
Crosstown rivals Adelaide had better news on the injury front with Wayne Milera expected to avoid surgery on his injured shoulder.
The Crows are hopeful Milera, who hurt his AC joint during the round five game against Gold Coast, could return within the next month.
Veteran midfielder Bryce Gibbs looks set to return to face Fremantle on Sunday after missing last week’s win over St Kilda with a stomach bug.
Gold Coast could welcome back Sean Lemmens (ankle) and Wil Powell (concussion) for Saturday’s trip to Perth to face West Coast.
Melbourne’s Jack Viney (shoulder), GWS star Lachie Whitfield (thigh) and Sydney’s Lance Franklin (hamstring) are among other big names set to miss round seven.