Brimson was the Maroons' 18th man for their 32-6 win in game two of the State of Origin series at Suncorp Stadium.
He played the last of his three Origins for Queensland in game three in 2021 after making his debut under former coach Wayne Bennett in the 2020 series opener as starting fullback.
Injury prevented him from finishing that 2020 series. Walsh will miss game three in Sydney this year through suspension and last year's fullback Kalyn Ponga has ruled himself out of the series to concentrate on Newcastle.
Brimson has missed games for the Titans this year with hamstring issues but is back to his best and will line up in the No.1 jersey against Canberra on Saturday.
"Every year I want to play Origin," Brimson told AAP.
"I enjoyed playing for Queensland when I did get the opportunity and my goal is to get back and play in the team.
"If I can keep playing well for the Titans then I give myself every chance.
"Fullback is the position where I am most at home and I feel as though I've come back well from injury. I still feel as quick as I ever was.
"I want to prove for the rest of the season that I can play 80 minutes as a fullback."
Queensland selector Darren Lockyer told the Nine Network that Brimson was right in the frame to slot in as Walsh's replacement.
"He is a team-first type player and comes with energy and trains well," Lockyer said.
"I just know that based on what I have seen at the Titans, and based on what he's done for Queensland, that he will give his 100 per cent best."
Hamiso Tabuai-Fidow has played fullback with great success for the Dolphins but Bennett has moved him to left centre for the round 18 clash with Brisbane.
Tabuai-Fidow has starred in the centres for Queensland this year and is one reason why the Maroons have already wrapped up the series and lead 2-nil.
Lockyer suggested the Maroons would be reluctant to change a winning formula.
"Hammer has been fantastic in the centres and in terms of continuity and minimising disruption ... the least amount of changes positionally is ideal," Lockyer said.
Dolphins coach Bennett agreed with Lockyer.
"I don't think they will change Hammer. I don't think Billy (Slater) will do that," Bennett said.
"Brimson is a wonderful young player."
Brimson said the Titans were just scratching the surface of what they could achieve this year.
Just outside the eight on 20 competition points, a win over the Raiders would see Gold Coast overtake them on points differential.
"We have a lot of home games to come which is exciting for the back end of our season," he said.
"I still think we will play finals. We have key players back and there is a lot of improvement in us."
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