Galea, 34, had delayed his retirement to play another year with the Rovers this term, and was prepared to play on, but couldn’t reach an agreement with the club.
He tweeted: “Thanks everyone for your messages about retirement. It’s been so amazing to play the game for this long. A huge thank you for all the support.”
The former Wests Tigers forward has made more than 100 appearances for the club since arriving in 2008.
When Galea’s departure was announced, Rovers chief Mike Smith said: “In the four years that I’ve been here, Ben has been a pleasure to deal with. He’s a consummate professional, both on and off the pitch”
Half-back Blake Green could also be on his way out, despite having two years left on his contract, with Wigan believed to be interested in paying a transfer fee to secure his services.