Sydney Roosters second-rower Mitchell Aubusson has vowed to step up in place of injured vice-captain Boyd Cordner, insisting the NRL club can excel in spite of their growing casualty ward.

Aubusson admitted the loss of Cordner, who injured his pectoral muscle in training and faces up to three months on the sideline, was a cruel blow for the premiership contenders on the eve of the season.

Cordner’s absence leaves a gaping hole in the Roosters pack, as does that of fellow vice-captain Jared Waerea-Hargreaves who remains sidelined with a knee injury suffered last year.

“Obviously they’re some senior members of our team and a big part of our go forward. They’re going to be a massive loss to us,” captain and hooker Jake Friend told AAP.

But Aubusson is confident he can steer the Roosters through the tricky opening rounds of the year.

The dependable and versatile Aubusson will be given an opportunity to cement a starting role when the Roosters face St Helens in the opening World Club Series fixture at Langtree Park on Friday (Saturday 0700 AEDT).

“It was obviously disappointing for Boyd to go down like that as he’s been one of our leaders and hardest trainers through the pre-season,” Aubusson told AAP on Wednesday.

“I think I’ll get a bit of a crack there on Friday night and hopefully I can do a good job for the boys.

“It’s going to be hard to replace Boyd, but if I get to play there I’ll do it in my own way and enjoy it.”

Even without their two highest-profile forwards, the Roosters will field an imposing pack led by New Zealand international Sam Moa and up-and-comers Kane Evans, Dylan Napa and Mitchell Frei.

It is some of the team’s younger players that Aubusson said will cause the most surprises to sceptics in the early rounds of the year.

“In the past three years we’ve built this club on creating depth and making sure that if some guys go down then the next guy has to step up,” Aubusson added.

“The guys have done that over the past few years and we find ourselves in a situation now where we have to do the same thing.

“I’m really looking forward to seeing a couple of the older guys run round and more so the young guys who haven’t played as much.

“I think there’s some young names who after Friday we’ll be talking about come Saturday morning.”