Penrith have arguably the worst injury toll of any side after six rounds of the Telstra Premiership, but a group of young replacements are proving the difference according to Panthers back-rower Corey Harawira-Naera.

The Panthers could be without as many as seven first grade regulars for their clash with the Cronulla Sharks on Sunday, but have still managed to win five of their first six games to sit in equal second on the competition ladder.

Not only is it Penrith's best start to a regular season since 1999, it is also a huge improvement on their dismal 2-7 opening to last year after having been installed as premiership favourite before a ball was kicked.

Their latest injury - to winger Josh Mansour (fractured cheekbone) - is another blow. It is hoped that Dallin Watene-Zelezniak will return from a fractured jaw for this week's clash.

Tyrone Peachey continues to play a Mr Fix it role at five-eighth with James Maloney stepping up in the absence of young star Nathan Cleary.

Second-year forwards Harawira-Naera and Viliame Kikau were dominant on the edges in the side's 35-12 win over the Titans on Sunday, while the club has been forced to blood the next generation early with Wayde Egan, Kaide Ellis and Christian Crichton all earning NRL debuts in recent weeks.

"It's just attitude," Harawira-Naera said of the ability of the side to keep winning.

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"We've got a few boys dropping through injury but everyone is coming in and taking over, looking after positions while they're away.

"I guess we're just wanting it more than other teams right now and it's showing on the scoreboard."

Harawira-Naera's shift to the centres on Sunday proved a masterstroke for Anthony Griffin's side with the Otaua junior scoring two tries and holding his own against Dale Copley.

The late switch was not a surprise tactic according to Panthers coach Anthony Griffin. Harawira-Naera has become familiar with the position during his time in the lower grades.

"I was a bit lighter back then," Harawira-Naera laughed.

"I haven't played 80 all year so it was good to get it all out, probably don't need to do as much work in the back-row but that probably helped me

"I was grateful for the opportunity, he could've done something else and put someone else there so just happy to contribute."

Penrith's opponents on Sunday the Sharks have an injury crisis of their own with concerns over Andrew Fifita, Wade Graham, Luke Lewis and Paul Gallen on the weekend, adding to a list that includes James Segeyaro, Jason Bukuya and Sione Katoa.