Erin Clark has also been released from the remainder of his deal with the Raiders, having joined the club in June after being released by the New Zealand Warriors.

Clydsdale is retiring to pursue business interests despite signing with the Raiders for 2018, just months after being released by Canberra to take up an opportunity with Cronulla.

The effect 24-year-old Clydsdale's move could have on the future of Kurt Baptiste is yet to be seen with the club needing to shed weight to become salary cap compliant.

Clydsdale looked set to fight it out with Garvey in a bid to play second fiddle to first-choice hooker Josh Hodgson, who has recently inked a long-term extension that will keep him in Canberra until the end of 2022.

But the Newcastle product has hung up the boots having battled to play regular first grade football since joining the Green Machine.

"Craig is a talented hooker who at 24 years of age is still learning and developing as a player who we believe can be a valuable addition to our squad in 2018," Raiders recruitment manager Peter Mulholland said.

"Adam Clydsdale has decided to retire from rugby league to pursue a career with his family business and we wish him all the best for the future.

"Erin Clark has also been granted a release from the remainder of his contract with the club, so having Craig in our squad gives us some stability in the squad."

Garvey has played 13 NRL games over the past two seasons with Canterbury, having spent three seasons with St George Illawarra, where he chalked up 10 first grade appearances.