When it comes to Nonu, it is best to never rule anything out and work on the theory that the more unlikely something sounds, the more likely it is that it could happen.
No player in New Zealand has a Super Rugby history quite like Nonu's and for him to end up back at the Blues for a third stint with the club, five years after he left, would be entirely in keeping with a career that has never been short of plot twists.
The prospect of him going to the Chiefs appears to be equally alive and that too would be a remarkable business because should it happen, it would be his fourth Super Rugby club, making him one of the few men in New Zealand to have worked his way through that many.
So could it really be possible that Nonu, whose last rugby act on New Zealand soil was to score two blistering tries at Eden Park in a crushing defeat of the Wallabies in 2015, is heading back to New Zealand for one last crack at Super Rugby?
The answer would have to be yes.
Mystery still surrounds his seemingly sudden and unexpected announcement in May that he would not be extending his stay with Toulon, the French club he joined after the 2015 World Cup.
He cited family reasons which could mean his family are homesick, or it could just as easily mean he was stiffed by the club but either way, he's not yet with a contract and despite his pedigree, there may not be a long queue of clubs looking to invest in a 36-year-old midfielder with a bit of a chequered history.
If Nonu really is leaving Toulon for family reasons then New Zealand is presumably the most likely destination for him to resume his playing career, but given he's not prone to orthodoxy, he could just as easily wash up in Romania or Georgia or the Faroe Islands.
But if any club would be willing to take the risk, it could be the Blues whose own coach, Tana Umaga, spent a lifetime with the Hurricanes, joined Toulon in 2007 as a player, became coach in 2008, came out of retirement in late 2009 to become player-coach and then returned to fulfil that same dual role at Counties-Manukau in 2010 where he was still good enough, at 38, to win a contract with the Chiefs in 2011.
Nonu may be equally willing to commit to Umaga, who was of course an early mentor at the Hurricanes where the pair of them formed a deadly midfield combination in 2003.
The presence of Sonny Bill Williams at the Blues also has to be factored in as he and Nonu have a bond both on and off the field that goes back to 2010.
Williams made his test debut in the midfield alongside Nonu at Twickenham in 2010 and with a touch of poeticism, the two were back in the midfield on the same ground for the latter's final test which was the World Cup final.
On a more practical level, the Blues arguably need a seasoned midfielder as George Moala has left and Rieko Ioane surely can't be used there again when he's so obviously better suited to the wing?
Nonu may be closing in on 37 but reports out of France suggest there is still a bit of running left in his legs and that he hasn't lost the art of smashing himself over the gain-line and taking his team forward.
Whatever perceptions may have arisen about his manageability off the field, no one has ever disputed he's a world class operator on the field with a vast range of deft skills to support his obviously destructive running power.
Which is why, no doubt, the Chiefs - whose coach Colin Cooper brought Nonu into Super Rugby at the Hurricanes in 2003 - has been careful to be non-committal about his potential interest in signing the veteran.
"We haven't talked about that," he said. "I'm just saying we haven't been discussing it. I'm not saying no or yes."
But like the Blues, the Chiefs have holes to fill as Charlie Ngatai, Johnny Fa'auli and Tim Nanai-Williams are all moving on.
And no doubt just like the Blues, the Chiefs will be weighing up whether the risk of signing Nonu would bring a suitable reward.