The 23-year-old, who will take up a contract with Northern Ireland club Ulster halfway through 2016, expressed a desire to play for the Blues before he left, and it was one the struggling franchise was eager to take up with New Zealand Rugby on his behalf.
In announcing his departure on a two-year deal, Piutau also expressed a wish to return to the Blues in a bid to again represent the All Blacks in the future.
He remains in the frame for this year's World Cup, but if he isn't selected, New Zealand Rugby's response will leave a bad taste. It will also force him to consider other overseas offers before he moves to Belfast.
It is a decision by the national body which might prompt questions from the struggling franchise's supporters about how far it is prepared to be involved in the contracting of players while allowing the John Kirwan coaching saga to run.
At the weekend, after a fortnight of reports about Kirwan's future and the revelations about an impasse at board level, New Zealand Rugby confirmed that it would help mediate in the messy affair.
Fullback Piutau, who has played 14 tests, is in the Blues' leadership group under injured skipper Jerome Kaino and would have been available for 11 matches next season before his departure. Given their record over the past four years, they aren't likely to be in the playoffs frame.
Blues chief executive Michael Redman said Piutau would have been an important element in next year's squad.
"Our argument was that next year has potential for all New Zealand teams to be disrupted by players coming in and out of the sevens environment," he said. "Our rationale was that Charles might have been with us for 11 weeks, which would have been better than zero."
Redman added: "We accept [New Zealand Rugby's] reasons for declining that. In many ways it comes down to the fact he wouldn't be available for the full season."
However, New Zealand Rugby allows players returning from overseas clubs to join Super Rugby franchises late in the season, even those who are not available for the All Blacks such as Crusaders' Fijian wing Nemani Nadolo.
When asked about the apparent anomaly, Redman said: "We accept that New Zealand Rugby will look at it in a case by case basis. We believe our fans want to see the best players playing every week and we support that."
The Blues would appear to need every quality player they can get their hands on. Piutau, out with a knee injury but who has been told he might not be far from a return, is a rare recent piece of good news for the Blues.
Kaino has been missing for two weeks after his compound dislocated finger suffered in the win over the Force and won't return this season, with Steven Luatua and Patrick Tuipulotu also long-term casualties.
Loose forward Luatua dislocated his shoulder in the Blues' recent 23-18 victory over the Bulls - only their third of the season - and also has nerve damage around the joint.
Lock Tuipulotu has a long-standing hip/groin problem which could require surgery which will put his World Cup in doubt, as revealed by the Herald on Saturday.
Prop Tony Woodcock is also unavailable to play the Hurricanes at Eden Park on Saturday due to a shoulder problem. In all, the Blues have 13 players on the casualty list.
- By Patrick McKendry
