But the former Queensland State of Origin hooker insists that's because his focus is solely on Newcastle after leaving Red Hill on good terms.

A veteran of 260 games for the Broncos and signed to the club since age 13, McCullough made the switch last week to Newcastle.

He is expected to start on Sunday against Penrith at Campbelltown Stadium as the Knights' new No.9 after Jayden Brailey's season-ending injury.

But when it comes to the Broncos' clash with the Eels on Thursday night, McCullough says it's unlikely he'll be tuning in.

"I probably won't (watch)," McCullough said.

"Just more so to keep myself away from football and to keep all my energy here with the Knights.

"I love those boys (up) there - they have been tremendous for me. I obviously wish them all the best.

"But my focus is all on the Knights and I just want to make sure I do everything I can to make sure I get the best result on Sunday."

A Queensland Origin player just two seasons ago, McCullough's minutes were reduced last year before Jake Turpin claimed the No.9 jersey from him in 2020.

It took him just days to link with Newcastle once the move was put forward, on a deal for this year only with an option for next season.

But the 30-year-old knew almost immediately it was time to get out of his comfort zone.

"You get a gut feeling when someone asks you a question and something felt right," McCullough said.

"Any change is outside of your comfort box. I needed to do that and I have done that.

"I could have sat at Brisbane and been content, but the challenge to come down and play some good footy for a new coach and team.

"With the team environment and the players here, it just ticked the box. I would be more dirty on myself if I didn't take the opportunity to do that."

Australian Associated Press