Oates out for a month with knee injury in Broncos blow

Brisbane winger Corey Oates has a knee injury that will sideline him for at least a month in a cruel setback to the Broncos ahead of Friday night's clash with South Sydney.

The 28-year-old suffered a posterior cruciate ligament (PCL) injury during Friday night's 26-16 win over Parramatta in Darwin, but battled on until the end of the match.

Broncos Head of Performance Dave Ballard said Oates would not require surgery but faced at least four weeks of rehab.

"He always works hard during his rehab periods and we will see him back ready to go before too long," Ballard said.

It is wretched luck for Oates, who was playing his first game in six weeks after breaking his jaw in the round two clash with North Queensland. 

Jesse Arthars, who replaced Oates while he was previously injured, will likely come into the side against the Rabbitohs at Suncorp Stadium.

The competition leaders will be without prop Payne Haas and No.6 Ezra Mam after both accepted one-match suspensions for hip-drop tackles against the Eels.

Former Wests Tigers playmaker Jock Madden will make his Broncos debut in place of Mam, while forward Keenan Palasia is likely to slot into the 17 for Haas.

Broncos prop Pat Carrigan said Madden had learned a lot from captain Adam Reynolds, coach Kevin Walters and assistant coach Allan Langer about halfback play and would perform well in the role.

Haas is virtually irreplaceable but Carrigan said he was looking forward to the team rising to the challenge without him.

"Last year we played Souths in Sydney when we didn't have him and we still got the result," Carrigan said.

The subject of hip-drop tackles dominated Carrigan's press conference

He was suspended last year for a third-man-in hip-drop. The game has had more one-on-one variations of the tackle, for which Haas and Mam were suspended.

Carrigan said the definition of what constituted a hip-drop remained unclear, and added no clubs trained to make such tackles.

"We are working here to try and not get in those positions and be better when you are under fatigue. It is a tough one," he said.

"Some are unavoidable. I think the NRL are learning on the run, as much as the players are. Sometimes accidents happen and there probably needs to be a little compromise in that regard ... but we don't want people injured."