Brisbane battering ram Tonie Carroll has put an end to rumours he will follow Wayne Bennett to the Dragons by today confirming he'll retire from rugby league at the end of the season.

And the powerful lock forward has fired a warning to Storm-killers Newcastle ahead of Friday night's emotion-charged battle at Suncorp Stadium.

Murmurs last month suggested Carroll would play for one more year after an approach from Bennett but the 32-year-old finally ended speculation this morning.

Carroll will instead take up a career as a Gold Coast real estate agent.

Brisbane expect a surging crowd for the meeting with the Knights, which is pivotal to the final make-up of the NRL top eight.

The clash with Newcastle marks the last official home game for Bennett and Carroll, with Broncos chief executive Bruno Cullen urging fans to stay after the game to honour the long-serving duo.

It is understood Bennett will be making a post-game address to thank the fans for their support during his 21 years at the Broncos, a tenure which has yielded six premierships in an unprecedented period of success.

Riding a surge of emotion in a game to honour departing hooker Danny Buderus, the Knights sensationally upset competition favourites Melbourne on Saturday to set up a mouth-watering final round clash with the Broncos.

But if Bennett is to spend another game in the Suncorp Stadium dressing rooms after Friday's clash, he not only needs to coach the Broncos to victory but must also rely on the team he will lead next year - St George Illawarra - beating Sydney Roosters.

If this scenario came to pass, Bennett would then be plotting the Dragons' downfall a week later as the Broncos would finish fourth and host the fifth-placed Dragons in the opening match of the finals.

If the Roosters lose to St George, the result of the match in Brisbane becomes academic as they would retain fourth spot and play the Broncos on Friday week.

The Knights, meanwhile, must win to ensure their own place in the finals. A loss could mean they miss the top eight if Canberra and the Warriors both win.

Carroll described Brisbane's defence in their scratchy win over the hobbling Bulldogs as "terrible" but warned Newcastle to expect a vastly different side on Friday night.

"They've (Newcastle) got a lot on the line this week," he said.

"Last week's win was for Beddsy, and well done to him. But this week they'll be up against a different Broncos side than they saw on the weekend.

"We had a bit of a hiccup on the weekend - our defence was terrible. The only reason we got through that game was because everyone wanted to win it. Everyone showed a bit of commitment.

"If we need to make a run at the finals, we have to pick that up."

When asked if Brisbane had the ability to win the grand final, Carroll didn't hesitate. "Definitely. Without a doubt," he replied.

"It would be a good way to go out. It would be a fairytale. (But) it's all up to us."

Carroll (cork), Karmichael Hunt (cork) and Justin Hodges (eye infection) are all carrying niggling ailments but will be fit for Friday night.