Concussion has forced Newcastle winger James McManus to retire from the NRL, effective immediately.
The 30-year-old hasn't played since he copped what appeared to be an innocuous head knock in a round-20 match against South Sydney in July 2015.
McManus, who scored 72 tries in 166 matches for the Knights, was advised by medical officials to make the call.
"It is obviously a difficult decision but a decision I made for my young family," McManus said.
"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 10 years.
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"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."
McManus played three State of Origin matches for NSW between 2009 and 2014, scoring one try.
He will move into a full-time role with the club in November as a business development executive after working with the Knights on a part-time basis this year.
"James is a player who is highly respected by everyone at our club," Newcastle chief executive Matt Gidley said.
"His dedication, commitment and professionalism ensured that he fulfilled his potential and was rewarded with representative honours."
