It comes as much-discussed Canterbury halfback Lachlan  Galvin joins Blues camp as a training player ahead of the decider in Brisbane.
With Kotoni Staggs axed following the game-two thrashing, Haas is the only NSW player representing the 13th-placed Broncos at Suncorp Stadium next Wednesday.
Reece Walsh and Pat Carrigan line up for Queensland, leaving Brisbane strapped for marquee talent as they fight to snap a seven-game losing streak that dates back to April.
If they fall to Cronulla on Saturday and Parramatta beat Manly the next day, the reigning premiers will finish the weekend 16th on the ladder.
It's been quite the fall from grace for the Broncos, who risk becoming the first team since 2006 to miss the finals the year after winning the premiership.
So it was with mixed feelings that Brisbane's best forward Haas entered Blues camp in the idyllic northern NSW town of Kingscliff on Tuesday.
"It's pretty hard coming into camp knowing we're in the kind of form we are," Haas said.
"You obviously want to help the brothers there, because that's who you bleed with since November (pre-season).
"To not be there, and just watch from the sidelines, you feel pretty hopeless. But I've got all the confidence in them to get the job done this week and keep our season alive."
Lifting Haas's spirits, brother Klese has been invited into Blues camp as a training player following a solid season with Gold Coast.
Galvin, the younger Haas, Sydney Roosters utility Hugo Savala, Melbourne's Tyran Wishart and Titans rookie Zane Harrison will all join NSW at various points of their Kingscliff camp, but are unavailable to play the decider.
Savala and Galvin were greeted by a media scrum on arrival at Gold Coast Airport on Wednesday, with the latter a lightning rod for criticism since his highly publicised mid-season move to Canterbury last year.
But amid a stronger 2026 season, Galvin's call-up as a training player is a vote of confidence in his future at representative level.
"He's a great player," Savala said of Galvin.
"I can't wait to spend a few days with him and train the house down and help the boys out to win the decider."
Brisbane will soon become enemy territory for Haas, who leaves next year to reunite with former Broncos coach Wayne Bennett at South Sydney.
The loss will rock the Queensland club, but Haas says the reception he will receive on return to Suncorp Stadium next year won't compare to next Wednesday night.
"It's not the same, to be honest, in an NRL game," Haas said.
"It's a different ball game when you're in a Blues jersey against Suncorp with all the Maroons people yelling at you, giving it to you.
"It's very hostile and it's very different."