Former Newcastle Knights winger Jake Mamo has retired effective immediately admitting that concussions and other niggling injuries played a role in his decision.

Mamo debuted for the Knights in 2014 – playing 29 games before switching to the English Super League where he played 102 games for Huddersfield, Warrington, Widnes before finishing up with Castleford.

“There were a lot of factors that came into the decision with the main one being that I’ve suffered too many head knocks and injuries,” Mamo said.

“I suffered a bad back injury in my last game against Saints and I couldn’t move for three days after that. I thought to myself that I never want to feel like that ever again.

Argument for Knights captain Kalyn Ponga to be moved back to fullback to save him from more head knocks doesn’t add up

“Rugby league has given me a lot and also given me the chance to move over here to the UK. I’ve had good relationships with fans at all the clubs I have been at and that is going to be the thing I miss the most.”

Meanwhile, the81stminute.com’s own Curtis Woodward is reporting on Twitter that Knights NRLW premiership-winning captain Millie Boyle has knocked back a “substantial” offer from the club and will instead leave the Knights to link up with the Sydney Roosters for the next NRLW season.