Not even Manly losing Brett Stewart could bring a smile from Gold Coast coach John Cartwright, ahead of a Monday night NRL clash he has labelled a "must win".

Capping an eventful week for Stewart, the former Test fullback was on Sunday ruled out of the Skilled Park clash after succumbing to a hamstring strain.

The second-last Titans had been steeling themselves for a pumped-up Stewart, after he came under fire for appearing to mock NRL boss David Gallop with his celebration during his three-try outing against Canberra last round.

Will Hopoate switches from wing to fill Stewart's spot at fullback, with ex-Test rep David Williams coming into the vacant wing spot.

Cartwright had his own concerns with the fitness of centre Bodene Thompson (virus) and trying to turn his team's form, after they slumped to a 3-6 record with last round's 34-14 Skilled Park loss to the Warriors.

Joseph Tomane is on standby for Thompson who will receive a final verdict an hour before kick-off.

While Manly might be reeling from Stewart's omission, the Titans are the ones feeling the pinch and they are 2-3 at home this season.

"It's a must win. Mentally, it is very important that we win ahead of our bye," Cartwright said.

"The competition table can slip away from you.

"We are not in a good position as far as that is concerned and we haven't been playing to our potential - that's the main concern.

"If we were playing decent football and we were losing, then you know it is going to turn for you, but we haven't been in great form consistently this year. But we are aware of that."

Titans interchange forward Ben Ridge appears to have overcome a shoulder complaint, while Manly co-captain Jason King (rib) also looks to have received the green light.

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