Whites Ferns all-rounder Leigh Kasperek is returning to Wellington after spending the past six years in the Otago set-up.
Her departure will break up the formidable combination she formed with Suzie Bates and Katey Martin.
The Sparks have relied heavily on the trio during the years. With Bates missing games in the past few seasons due to other cricket commitments, Otago's prospects have rested more heavily on Kasperek's shoulders. And she delivered some terrific individual performances.
In 50 one-day games for the province, the off-spinner took 89 wickets at an average of 18.65 and scored 1364 runs at 31.
The right-hander's Otago twenty20 record is very decent as well. She took 36 wickets and scored 458 runs in 33 games.
During her tenure, the Sparks collected two national titles - the twenty20 crown in 2016-17 and the one-day banner in 2013-14.
Kasperek is in the United Kingdom playing cricket for Yorkshire and will move to Wellington in September.
"I really enjoyed my time with the Sparks and will look back fondly at many great years of cricket," she said in a press release.
"However, I'm excited for the new challenge that awaits in Wellington and look forward to linking up with the team for the coming season."
The 27-year-old, who was born in Edinburgh, made her White Ferns debut in 2015 and is ranked by the ICC as the fourth-best T20 bowler in the world.
She has represented New Zealand 64 times and played at three world tournaments.
Sparks coach Nathan King said Kasperek made the decision based on what was best for her cricket career.
"She felt the Wellington environment can give her a bit of a fresh start," he said.
"And she wants to be the best possible cricketer she can be and feels she can do so in Wellington.
"It is a huge loss. With her quality it is like losing two or three players."
Her absence will open up opportunities for spinners Eden Carson and Sophie Oldershaw.
Wellington captain Liz Perry was thrilled Kasperek would be joining the Blaze.
"We want to be the leading domestic team in New Zealand ... and Leigh will be a great addition both on and off the field," she said.
"Leigh is an exceptionally talented cricketer who has really started to dominate domestic cricket with bat and ball.
"She will be a key driving force for success within the team as she is always hungry to be better and this will encourage those around her to follow in her footsteps."
