Jared Waerea-Hargreaves isn't going to go into his shell during the 2014 finals series.

Roosters enforcer Jared Waerea-Hargreaves says the Tricolours won't be dialling down the aggression this Saturday against Penrith, despite key men Aidan Guerra and Dylan Napa being sidelined through suspension.

Earlier in the week coach Trent Robinson admitted his chargers "did go a bit too far" as the premiers aimed to rattle the star-studded Rabbitohs pack last Thursday night.

Guerra was hit with a one-match ban for a chicken wing tackle on Kyle Turner, while Napa has been rubbed out of the Roosters’ next two matches for a shoulder charge after having the offence downgraded at the judiciary.

But speaking ahead of his side's showdown with a Panthers outfit featuring heavy hitters Nigel Plum and Sika Manu, forward leader and vice-captain Waerea-Hargreaves says the Roosters famed physicality will be crucial to gaining an advantage up-front.

"We'll be trying to win those little battles through the middle, and our fast, aggressive style is a big part of that," Waerea-Hargreaves tells NRL.com.

Asked whether the Roosters crossed the line against the Rabbitohs, the Kiwi prop responded: "I don't think so, no, not at all.

"I think we laid a strong platform last week against Souths, we needed to against their pack. And we'll try and get out there on Saturday and do the same.

"They're also quite large themselves so it's going to be quite a good challenge there in the middle."

Fast developing a reputation as one of the most aggressive young bucks in the game, 21-year-old Napa knows the NRL's shoulder charge ban means he has to take the tackling style out of his game. 

In Round 3 against the Broncos, Napa was cautioned by referee Shayne Hayne over his risky technique, while the two-game suspension for his hit on John Sutton means he won't play again until grand final day should the Roosters get past Penrith.

But Waerea-Hargreaves, cut from the same cloth as his fiery young teammate, says while he has had a quiet word to him about toeing that fine line between aggression and over-the-top, he urged Napa not to change the stripes that have seen him ear-marked as an Origin player of the future.

"Yeah, ‘Naps’ and I get along really well, so we have spoken about it," says Waerea-Hargreaves.

"But what he's got is something you can't coach. That aggression is a great part of his game and he's fortunate to have it. 

"It's a pretty important key to us and our team. That's his game and that's his style of footy, and it's massive for us."

As well as the notable absences of Guerra and Napa, the premiers’ much-vaunted pack will again be without star hooker Jake Friend and Kiwi back-rower Frank-Paul Nu'uausala, who are both aiming to return from chest and foot injuries respectively over the next fortnight. 

Utility Mitch Aubusson will again slot into the No. 9 jumper after performing admirably in the 22-18 defeat of Souths, while Isaac Liu has been named to start at lock with Kane Evans joining the bench. 

 This time last year the Roosters overcame Manly 4-0 in a finals epic without key forwards Waerea-Hargreaves (suspended) and Boyd Cordner (ankle injury), and they have also had to get by without the likes of Sonny Bill Williams, Cordner, Guerra and Friend at various times throughout this season.

Waerea-Hargreaves is confident these performances in the past without their full complement of stars will stand the Chooks in good stead throughout the finals series.

"The culture that we've built here at the club, it doesn't matter who's in the team or in the forward pack, we're still going to play our style of footy and our natural game," Waerea-Hargreaves says.

"That's just what we do, and it's good to see the young boys who come in and fill the spots don't have any issues with getting the job done.

"Whoever it is we've got faith in them, and know each one will do the job."