Gold Coast coach Miron Bleiberg disagrees marquee man Jason Culina is struggling and predicts an upset of Sydney FC will silence the "vultures" and resurrect United's lofty A-League ambitions.

Culina's form has come under criticism in recent weeks as United slumped to two straight losses, with former NSL-winning coach Nick Theodorakopoulos suggesting the Socceroos midfielder was trying too hard.

Australia coach Pim Verbeek even admitted during the week Culina "had played better in his life", but insisted he was not worried about his influential midfielder.

Bleiberg was reluctant to comment on criticism of his marquee player ahead of Saturday's match at Skilled Park but was clearly at odds with perceptions of Culina's form.

"Jason is on everybody's lips because Gold Coast United has been on the back foot," Bleiberg said.

"(On) the subject of Jason, `no comment'. But I tell you in one word: `I disagree'.

"I tell the players `when you have a headache you go and take a tablet.

"When you are on the back foot the football industry is full of vultures so it's like when you have a headache take a tablet'.

"A win will be like a tablet."

It isn't just Bleiberg talking down suggestions of a form slump for Culina, with Sydney FC defender Simon Colosimo also leaping to his defence.

"Even if you say his form has dipped, if you still go through and if you really analyse his game individually, you see he still gets so much of the ball and every time he gets it he's a threat," Colosimo said.

"I don't think his form has dropped all that much, I think there's going to be those days where that pass isn't going right for you, but it's definitely not a worry for them.

"It's a worry for us because he's going to come out like he does every game and want to hurt teams and play well."

Bleiberg identified Colosimo as one of table-topping Sydney's greatest strengths this season along with dangerous striker Alex Brosque, who set up all three goals in last week's 3-0 win over Wellington.

"Brosque, he played brilliantly in year one and then he disappeared, and now he plays brilliantly, even better, because he's a bit older and more experienced," Bleiberg said.

"When he was at the Roar he carried the team on his shoulders and now he plays even better and that's credit to the coach that he's got the best out of him.

"That also applies to Colosimo, they are blossoming under him this year and that's one of the strengths of Sydney."

Sydney's defensive stocks have been boosted for Saturday's match by the return of Swiss defender Stephan Keller but coach Vitezslav Lavicka could keep faith with Seb Ryall and Shannon Cole in the starting line-up.

Gold Coast welcome back Kristian Rees (hip), who is likely to line up along surprise teenage selection James Brown in defence.

Fellow young gun Mitch Bevan has been named on the bench after one of the best goals seen in the youth league.