The experienced NRL hooker will line up for new club Newcastle on Thursday in Gosford, less than a month after quitting the Broncos to join the Knights.

While there's no hard feelings with a player who is still well respected by those at Red Hill, McCullough shouldn't be expecting any favours from his old clubmates.

"I can't wait," Broncos enforcer Joe Ofanhengaue said.

"It's going to be a bit weird going up against him. Everyone here's good mates with Macca we all love him and we're just really proud that he got his opportunity over there.

"But now we're playing against him ... we've got to try something new this week. He's going to be over there snitching on us."

The Broncos suffered a blow on Sunday with centre Kotoni Staggs going down with a hamstring injury in training.

Scans on Monday revealed a partial muscle tear, but no tendon damage - bitter sweet news that could still see the form centre out of action for up to six weeks as the Broncos try to end a three-game losing run.

The return of Tavita Pangai Jnr from suspension and captain Alex Glenn from a calf injury is a bonus for the Broncos, who are also poised to sign experienced New Zealand international Issac Luke on a short-term deal.

Former Bronco Peter Ryan has also come in as a defensive coach and Ofahengaue's said he'd made an instant impact on the team in Sunday's training session.

"He stripped us down to our basics," Ofahengaue said.

"With anything, if you want to learn it, the best way you strip it down to the basics and Rhino's done that.

"15 minutes of him, but it was it was powerful, you know, the little time that he gave us I took a lot out of it."