Papalii earned his early reputation as a feared hitman when the then-20-year-old targeted and out-pointed Gallen with some brutal tackles in the 2012 NRL finals series, Gallen later accusing him of a "dog shot".

Gallen leads a contingent of Sharks players who officially return from controversial doping sanctions for the NRL season-opener against the Raiders on Sunday.

The bans, which essentially amounted to three NRL matches, were issued in the week before Cronulla's last game against Canberra, in round 24 last year.

Papalii would not speculate on whether the Sharks would have additional motivation for their official return, but he put to rest any lingering tensions between himself and Gallen.

The pair have been Australian Kangaroos teammates since 2013 and Papalii said he now considered Gallen a respected mentor.

"Obviously 2012 was a long time ago. Since then we've played in a couple of teams together," Papalii said. "I've learnt from him. I got to go to his [boxing] sparring sessions in England and we've become pretty close off the field. All you want to do is learn from the best and Gal's one of them.

"You don't go on the field wanting to be hated or trying to do something to other players. I guess the relationship has changed since that game."

But Papalii has urged the Raiders pack to become more aggressive. The Raiders have not played finals since that 2012 season, finishing 13th and 15th in the past two years.

The Raiders pack has been boosted by the recruitment of premiership-winning forwards Frank-Paul Nu'uausala and Sia Soliola, plus England representative hooker Josh Hodgson.

"They bring a lot of aggression as well," Papalii said.

"I see our pack as one of the biggest. As a pack you want to be feared and we haven't been doing that, but hopefully this is our year and hopefully we can dominate.

"With the roster we've had ever since [2012], I believe we could have played finals footy every year, but the NRL's a tough competition and anything can happen. Hopefully this year we gel as a team."

Having endured a horrific 2014, the Sharks showed signs of a revived and inspired team by finishing runner-up to premiers South Sydney at the Auckland Nines.

But Raiders captain Jarrod Croker denied the Sharks would be any more driven than other NRL rivals.

Croker put the blowtorch back on his own teammates, saying Raiders players should be driven by internal competition for spots this season.

While he tipped Blake Austin and Mitch Cornish to complement each other as Canberra's new halves combination, Croker said players like Sam Williams would continue to assert pressure from NSW Cup.

"Sammy Williams is very lucky not to be there as well, he's ready to go if someone doesn't perform consistently. That's a good position to be in for us," Croker said.

"We haven't had this sort of competition for spots, especially in key positions around the hooker and half areas and we've got some big forwards fighting for spots as well. The boys going out there on Sunday are going to have to perform because the pressure's on.

"If we can keep injury free and keep the heat on for positions, it's only going to make us a better team and better club."