It's understood that Barrett is on track to sign a similar deal to Brodie Retallick, where he will commit through to the 2023 World Cup but with a pre-agreement to take time off in 2020.
As much as he needs that time away to re-boot physically and mentally, he'll need to be wary that if he's unavailable for the All Blacks in 2020, he'll face a stiff challenge to wrestle back the No 10 jersey in 2021.
Richie Mo'unga is already breathing down his neck with half the country adamant he should be starting even now.
What primarily separates the two at the moment is test experience but if Mo'unga is given a full season in the role next year, while Barrett is either travelling the world, writing his memoirs, tidying his garage or playing in Japan, there could be a real selection ding-dong between the two in 2021.
The old adage of never giving a sucker an even break is potentially going to be ignored by Barrett who, despite his undoubted ability, experience and maturity, is going to have to some extent prove himself all over again in 2021.
And, frankly, if he comes to the Blues to do that, it could end up being a big mistake. Huge, in fact, as the Blues, despite having fixed their ridiculous split governance structure and having a skilled, compatible and effective coaching trio at the helm, are in worse shape than they have ever been.
Worse, because what is undeniable now is that they continue to chronically disappoint because their squad is full of players who for one reason or another don't appear to have the mental resilience to develop their decision-making and skill execution.
Sonny Bill Williams was right to say this week that the glass half-full brigade can look at the last two weeks and see that the Blues, who drew with the Bulls and then lost by a point to the Reds, missed the playoffs by the narrowest of narrow margins.
But the glass half-empty brigade will take no solace from getting so close because they will have seen how the Blues lacked composure, patience and discipline in the final quarter of both those games, just as they did in the final quarter of their opening fixture of the season against the Crusaders.
There was only limited, if any, progression in the team's ability to learn, adapt and grow and unless there is a massive clear out of personnel and major rebuilding of the squad, Barrett will be signing up for weeks if not years of frustration, disappointment and ultimately regret if he decides to sign with the Blues.
As much as it would be a massive coup for the club to sign him, he can't turn the Blues around on his own and he must know this.
He, like everyone else, must have looked at the Blues and wondered why they can't build themselves into a cohesive force given they have obviously good players such as Rieko and Akira Ioane, Tom Robinson, Patrick Tuipulotu, Ofa Tuungafasi and Dalton Papali'i.
A world class No 10 can make all the difference, but not if he's plonked behind a pack that can't stay on the front foot or a halfback who changes every other week or a midfield that doesn't have the full range of skills to break a tight defence.
Barrett, if he comes, would solve one problem, but the Blues need a ball-winning lock, a better halfback, a fullback now that Melani Nanai is going and two quality midfielders to replace the likely departures of Ma'a Nonu and Williams.
It's a significant shopping list and one the Blues, on historic and indeed recent evidence, are unlikely to successfully fulfill.
Established Super Rugby players with genuine All Blacks ambitions haven't come to the Blues in the last decade and just last week the impressive fullback-cum-wing Will Jordan opted to stay with the Crusaders where he will be in a five-way fight for game time rather than opt for the certainty of starting each week for the Blues.
Maybe Barrett will be the catalyst for change and his presence at the Blues, should he be there, will be enough to persuade other top players to come north and take up the challenge of dragging the club off the floor and into champions.
It's a big maybe, though, as why would someone such as Jack Goodhue, who is also believed to be on the Blues radar, going to be persuaded to give up playing for the Crusaders where he's won titles and established himself as an All Black?
His twin brother Josh is at the Blues but that hardly seems enough to mitigate the risk of coming to a club that has done so little to convince that it can get its act together.
Also weighing against the Blues is Auckland's out of control house prices, traffic congestion and perception for those who grow up in the provinces as a big scary place.
The club does typically pay better than the other four New Zealand Super Rugby teams but money can't be used to blind good players from seeing that the Blues have some indefinable issue preventing them from being able to play consistently good rugby.
It is possible that it is the enormity of the challenge that appeals to Barrett.
Perhaps Barrett realises that he'll be in a dog-fight for the All Blacks No 10 jersey and that by being at the Blues, he'll be forced to dig deep into himself each week to find answers to the myriad problems he'll inevitably face.
The Blues could provide him with a new lease of life – challenge him in different ways and make him a better player as a result.
Dan Carter, after all, thought long and hard about whether he too wanted to be the man to try to fix the Blues in 2009.
Carter, who was in a similar stage of his career as Barrett is now, liked the idea of swapping the comfort and safety of the Crusaders for the unknown of the Blues.
He only liked the theory of it, though, and when he considered what his life would like battling each day at a club that had no set direction or vision for what it wanted to be, he opted for the Crusaders.
Right now, it feels that Barrett would be best advised to make a similar decision and not take it upon himself to try to fix the Blues.
Potentially joining the Blues could make him, but more likely, it will break him. See him turned into a frustrated genius rather than the genius he currently is most weeks with the Hurricanes.
Joining the Blues is a risk he doesn't have to take and one that doesn't have any easy to see or immediate rewards attached to it.