In one of the toughest weeks in its young existence, Gold Coast SUNS appear certain to cop another blow with Campbell Brown in extreme doubt for Saturday night's visit from North Melbourne.

Brown injured a knee in last week's 95-point loss to St Kilda and was restricted to jogging a couple of laps at Suns' training on Friday morning.

Gold Coast SUNS coach Guy McKenna did not rule the Hawthorn premiership player out, but suggested Brown would be a doubtful starter.

"We'll wait and see, but his training today he certainly didn't look free," McKenna said.

"We'll assess that and see how he pulls up tomorrow. Each day he's got slowly better, but looking at what he did do today, if that's enough to convince the conditioning staff and footy staff, I'm not too sure."

Brown's injury concern comes at the backend of a week that has seen the SUNS widely criticised for their effort against the Saints and their progress in general.

McKenna said the criticism had been fair and it was now "time for action".

"I think enough's been said. It's time to put those words into actions and start standing up for ourselves," he said.

North Melbourne premiership player David King has led a chorus of commentators questioning what the Suns stand for with their play.

McKenna said it was hard to defend when they were playing so poorly.

"We know what we do stand for, we know how we want to play," he said.

"We want to defend like St Kilda and we want to attack like Geelong, we think that's the modern way of playing football, a hybrid of the offensive and defensive models.

"Quite clearly we don't look like that right now. We understand what we stand for, so when people say that, I think it's a sign of laziness on their behalf.

"Right now it's easy for them to say that and it's very hard for me to defend that."

The SUNS have made five changes for the Kangaroos match, with Zac Smith, Joel Wilkinson, Kyal Horsley, Liam Patrick and Taylor Hine coming in for Josh Toy, Matt Shaw, Alex Sexton, Aaron Hall and Andrew McQualter.

McKenna said the benchmarks against North Melbourne were simple.

"I'd think they'd be thinking about one thing, getting some respect and showing some fight," he said.

"If you can't stand for anything, you've got to at least stand for the jumper. There's people on the Gold Coast that have put this club up, set this club up, defined this jumper, defined its colours.

"We've got to bring that jumper to life. We've been preaching that for three of four years and it's now time we start to do that."