"We are going to have to wait and see," Pearce said. "We want them (Williams and Friend) fresh at the back of the year and we have a couple of important games coming up."
After a slow start to the year that saw them lose five of their opening 10 games, Pearce felt the Roosters had turned the corner since losing to the Knights, posting three straight victories over the Dragons [30-22], Titans [26-18], and Tigers [48-4].
"I don't think we are too far off people keep saying that we have been a fair way off but we are still winning games which you are after," he said.
"There were a couple of games there we should have won but we have learned from them and hopefully that holds us in good stead coming into these big games now. Last week in the second half we have attacked as well as we have for a long time, even though the Tigers might have dropped off, we still stuck to our guns."
The Warriors are strengthened by the return of damaging centre Konrad Hurrell but coach Andrew McFadden could spring further surprises to his line-up after naming an extended seven-man bench earlier in the week.
With Thomas Leuluai and Nathan Friend both showing good form and deserving of starting positions, Chad Townsend's place at five-eighth could be at risk.
McFadden was coy about his team, saying: " We'll have to wait on a few players but I'm pretty confident everyone will pull through."