Brad Fittler had to pass a demanding series of physical tests to prove he was ready to play again, before his comeback to rugby league was cleared by the NRL.
Fittler's return at next month's Auckland Nines for the Sydney Roosters was given the green light at a promotion for the event on Wednesday.
But NRL head of football Todd Greenberg said that was only after the former Kangaroos skipper passed a range of tests designed to identify whether he was physically prepared, or not, for a return.
And after training with the Roosters for the past two weeks Fittler said he was confident his comeback would be a success.
"Sitting there watching the Roosters play last year I don't think I have seen a group play with such spirit in the last 12 years, so it's about being part of that group," Fittler said.
"I have had a few sessions with them now and it gets the blood boiling again.
"They are a great group to be around. They work hard for each other and I know they will look after me. The sessions I have had with the Roosters have been great."
Greenberg said Fittler had proven he was ready.
"We put together a set of criteria, not specifically for Brad but for any retiring player who wanted to be eligible for registration in this competition," Greenberg said.
"It is an onerous set of criteria to step through.
"The club doctor had to put him through a range of very physical performance tests. There was a number of skill-based tests, they then had to write to us and put that in a document which effectively sat behind his contract as one of the special conditions.
"What we want to know is that someone is prepared physically and mentally to put themselves into this tournament. That is really important.
"I have spoken to Brad and I know he is training very hard and I know he will do everything required of him.
Fittler is only registered with the NRL for the Nines tournament with that registration to expire on Monday February 17.