Great Britain international Brian Carney has retired from all levels of rugby league with immediate effect.
Carney had a superb season with the Knights last year
The 30-year-old winger, who left Wigan for Newcastle Knights in 2006, only started training with his new club Gold Coast Titans on Monday.
But Carney says he wants to spend more time with his family and return home to complete his university studies.
Carney has requested the Titans hold back his release so that he will be unable to play for any other club.
Now it is time for me to make a decision that is in the interests of my family
"I have made this decision with a heavy heart and it has been a difficult decision for me to make," he said.
"I want to return home so I can go back to the UK to finish my Masters and to reunite with my family.
"I couldn't act like a fraud by taking the club's money, I knew in my heart I couldn't see the year out.
"Continuing on would have been for all the wrong reasons and I have never played the game for money, it has been for the challenge and I know my mind is not up for this new challenge.
"I have told the Titans to hold back a contractual release to ensure that media speculation is not about me doing this to go back to Great Britain to play rugby league or rugby union.
"I have always made decisions for me and now it is time for me to make a decision that is in the interests of my family."
The former Wigan star signed a deal with new Australian club Titans back in 2005 with the aim joining up with them for their first season in the NRL this year.
He was released early from his Wigan contract at the end of the 2005 Super League campaign and spent last year with the Knights - scoring 16 tries.
I would like to personally thank Brian for his integrity
Titans managing director Michael Searle
But after joining up with new team-mates at the start of the week, Carney announced that he would not see out his two-year deal.
"We totally support Brian in his decision to retire from professional football and support his decision to return home to commence his Masters study at University and to be with his family," said Titans managing director Michael Searle.
"I would like to personally thank Brian for his integrity and the manner in which he handled this, he had the fortitude to do this face to face and that strength of character is rare today.
"Only a footballer knows when it is time to retire and Brian has been struggling with this decision for some time and we wish him all the best in the future."
He is a clever person who can probably achieve in whatever he sets his sights on
Great Britain captain Jamie Peacock, currently in Ireland with Leeds Rhinos on a pre-season training camp, said: "Brian is an outstanding person and player and I know he will have thought long and hard about this decision.
"He is a fantastic talent who always performed at his very best, be it for Gateshead, Hull, Wigan, Newcastle, Ireland or Great Britain.
"He could turn his hand to anything in the future. Perhaps a role in the media would be good for him, although he is a clever person who can probably achieve in whatever he sets his sights on."