Australian all-rounder Lisa Griffith has returned home as planned and has been replaced by Adelaide Strikers legspinner Amanda-Jade Wellington.
The other change sees medium pacer Marina Lamplough get the nod ahead of spinner Bhagya Herath.
The Sparks twenty20 campaign is hanging by a thread following four losses in their first five games.
Otago has back-to-back games in Alexandra before the new year and realistically must win both to keep its playoff prospects alive.
The Sparks host Northern Districts at Molyneux Park tomorrow and play Canterbury the following day at the same venue.
Wellington may have timed her arrival perfectly. Last year the Molyneux Park pitch was slow and low and turned quite a bit.
It is expected to have more pace this year but should still suit Wellington, who is fresh from an impressive campaign in the Women’s Big Bash League (BBL).
The 22-year-old took 16 wickets at an average of 20.25 and is very capable with the bat. Wellington whacked 55 from 33 deliveries in the final against the Brisbane Heat.
The Heat got up to win the match but it was a very handy knock from Wellington and she outshone high-profile team-mates Suzie Bates and Sophie Devine.
Wellington has played 12 one-dayers, eight T20s and one test for Australia but was overlooked for selection this year.
Sparks coach Nathan King is hopeful Wellington will have a similar impact in the Super Smash as she had in the BBL.
"She smashed it around and is quite an explosive batter," King said.
"We were keen to get Amanda-Jade out for the whole tournament just so we had an extra spinner, but it was not to be. But I think her arrival will balance the attack nicely."
Lamplough’s inclusion is also about balance. She is on the slow side of medium and King is hoping her pace will prove hard to get away.
Injured all-rounder Hayley Jensen has been included. She fractured a bone in her hand earlier this month but she is confident she will be fit to play, King said.
Women’s twenty20
Molyneux Park, tomorrow, 12.40pm
Otago: Suzie Bates, Millie Cowan, Katey Martin (captain), Hayley Jensen, Hannah Darlington, Amanda-Jade Wellington, Bella James, Caitlin Blakely, Sophie Gray, Eden Carson, Emma Black, Sophie Oldershaw, Marina Lamplough.
Northern Districts (possible): Katie Gurrey, Bernadine Bezuidenhout, Felicity Leydon- Davis, Kate Anderson, Brooke Halliday, Eimear Richardson, Lily Mulivai, Olivia Lobb, Carolyn Esterhuizen, Charlotte Sarsfield, Lauren Heaps, Shriya Naidu.
