Chiefs loose forward Michael Leitch says he has committed to play for the Sunwolves, possibly as early as next year.
Japan captain Leitch, 28, told Fairfax Media he has signed to play his Super Rugby for the Japanese franchise in 2019.
There a possibility he could represent the Sunwolves next year but that is still to be negotiated.
The 47-Test veteran says bringing many of Japan's premier players together in the same Super Rugby team will be beneficial to their chances of performing well when they host the 2019 World Cup.
"If you look at it, it's a great building block using the Super Rugby to build the (national) team," he said.
One of his 18 Tests as skipper was the Brave Blossoms' famous upset of South Africa at the 2015 World Cup.
Leitch has played 29 games for the Chiefs since his first match in 2015 and has been a consistently strong performer.
Their next match is against the Sunwolves, in Hamilton on Saturday.