Brisbane are hopeful halfback Adam Reynolds will be back on deck for next week's Queensland derby with the Gold Coast Titans.

Reynolds, who has played a key part in the Broncos' surge into NRL's top eight, failed a fitness test on his groin on Thursday and withdrew from Brisbane's 36-12 win over Newcastle.

That's despite coach Kevin Walters saying on Wednesday that Reynolds had assured him of his fitness and that he would be "very surprised" if he didn't play.

Brisbane took a cautious approach, with Walters opting for Ezra Mam to debut alongside Tyson Gamble in the halves.

After the win over the Knights, Walters was upbeat that their star recruit will be primed to return against the Titans at Suncorp Stadium next Friday.

"We believe he'll be back next week." Walters said.

"Obviously if he's not ready to go, we'll rest him but I believe he will be ready to go next week."