Sopoaga has capitalised on his prestigious All Black status by signing a two-and-a-half-year deal with the London Wasps that is expected to be worth around $NZ1.13 million a season.
Sopoaga has been signed as a marquee player, which places his salary outside the cap.
New Zealand Rugby has a longstanding policy of not selecting players who play overseas, eliminating any likelihood he will don a black jersey when the 2019 tournament in Japan rolls around.
Although he was behind two-time World Player of the Year winner Beauden Barrett in the pecking order for the number 10 jersey, Sopoaga was seen as a lock to join the squad next year as the incumbent reserve playmaker.
Chiefs and All Blacks fullback Damian McKenzie, who spent most of last season in the 15 jersey, and Crusaders standoff Richie Mo'unga, are looked at as the likely options to now back up Barrett.
Both are seen as huge up-and-coming talents, but lack the experience in the international playmaking role that Sopoaga has accrued over his time in the black jersey, most notably in his debut in 2015 against South Africa, when he scored 12 points.
Although he was highly regarded after his strong start in South Africa, he failed to qualify for that year’s World Cup, and spent the majority of his international career coming off the bench.
When given a chance to start last year, against Argentina, he passed on the opportunity to return to New Zealand for the birth of his daughter, Milla.
He also was the star playmaker for the Highlanders, who won their first Super Rugby championship with him at the helm in 2015, the year he was also the competitions top point scorer with 191.
Playing for the All Blacks disqualifies the 26-year-old from representing the Cook Islands in the 15-a-side game, but like Tim Nanai-Williams (who has played for New Zealand in sevens and Samoa in 15s), he could be eligible to play for the Kukis in sevens.
The rules state a player can represent a different country at sevens level provided they have maternal links to the country, and a representative from the Cook Islands Rugby Union said that they would “absolutely” be open to that possibility.
“There is only a short window (of opportunity) for rugby players, so we congratulate him on being able to make as much money as he will going overseas,” the spokesperson said.
“And we would be very much open to the possibility of him playing sevens for us if he is.
But in the meantime, we say good luck and God bless.”