Newcastle Knights' winger James McManus has announced his NRL retirement due to health reasons.

McManus is proudly a one-club player who made his NRL debut in 2007 and went on to play 166 games for the Knights, scoring 72 tries.

Injury had sidelined the 30-year-old indefinitely this season, before he was medically advised to call fulltime.

“It is obviously a difficult decision but a decision I made for my young family,” McManus admits.

“I could never have dreamed that when I moved from the Northern Territory to Newcastle, that I would have got to play one game let alone playing the game I love for ten years.

“I am very privileged to have played my whole career at the one club and I am very honoured to have worn the Newcastle Knights jersey.”

In 2009 McManus made his debut for the NSW Blues, and played a total of three Origin games, while also representing Country on five occasions.

“James is a player who is highly respected by everyone at our Club,” CEO Matt Gidley said.

“His dedication, commitment and professionalism ensured that he fulfilled his potential and was rewarded with representative honours."

McManus has worked with the Club in a part-time capacity this season but will take on a fulltime role from November as Business Development Executive.

“I have really enjoyed working on the business side of the Club and look forward to continuing to add value into the future,” McManus concluded.

The Knights will celebrate James McManus' career this Sunday, with the flying Scotsman doing one final lap to farewell the fans before the NRL match kicks off at Hunter Stadium.