Fellow White Ferns Katey Martin and Leigh Kasperek will miss games as well. English import Beth Langston is not returning for a third stint while former White Ferns spinner Morna Nielsen has retired.
But there has been one significant gain. Top-order batsman Millie Cowan has returned after a year away from the game.
She smacked her maiden century in January last year but took a break from the sport to focus on her studies.
The 25-year-old had always looked more like a hockey player who dabbled at cricket. But her swashbuckling 105 from 85 balls helped rewrite that perception.
That hitting power was sorely missed last season. The Sparks finished last in the twenty20 tournament and fourth in the one-day competition.
The Sparks had to make do for long periods without Bates, who once again has playing commitments overseas and will not play much cricket for her province this summer, coach Nathan King said.
"It is not just what she adds as a player but also what she provides the players around her with and what they learn from her. That is probably the biggest thing we will miss from my perspective," King said.
Martin, who will captain the side, and Kasperek will miss "a couple of rounds" due to national duties but are otherwise available.
King said he was looking in to getting a replacement import for Langston but "nothing was confirmed at this stage".
All-rounder Megan Meltzer and medium pace bowler Marina Lamplough come into the squad. Meltzer is in year 12 at St Hilda’s Collegiate but has shown promise with both the ball and bat, while Lamplough has moved to Dunedin to study and will get opportunities to impress.
"I think we showed last year that we were a really competitive team but were on the wrong side of the ledger on a few occasions. But there is a real opportunity to change things this year.
"A lot of these players have experienced some success in previous seasons. The ability is certainly there within the group."
The Sparks will play in the McCullum Cup T20 competition in Dunedin tomorrow and Friday.
The team will then head to Timaru to play back-to-back T20s against Canterbury on Sunday. It is the last-hit out for the side before it opens its campaign with a series of T20s in Lincoln next week.
Otago plays Auckland on October 25 and Central and Northern Districts the following day. The Sparks will complete the first phase of games with a match against Canterbury on October 27 and Wellington the next day.
The next assignment after that is not until its one-dayer against Wellington at the Basin Reserve on November 17 — a three-week break.
There is another lengthy hiatus in December and a month-long gap between the end of the T20 tournament in mid-January and the resumption of the one-day competition in mid-February.
It is a stop-start season which King felt would present a challenge for his side.
"It is really going to highlight the structures that the associations have in behind their teams. Because the games are so spread out, the games that they are playing in between the domestic games are going to be really important."
With no women’s club tournament in Dunedin, King said it was hard to keep his side "ticking along" during the breaks.
"We have some things scheduled in but it is going to be an ongoing challenge."
Otago Sparks
2018-19 squad
Katey Martin (captain), Suzie Bates, Emma Black, Caitlin Blakely, Ella Brown, Olivia Gain, Georgia Clarke, Millie Cowan, Megan Gibbs, Georgia Heffernan, Kate Heffernan, Polly Inglis, Bella James, Leigh Kasperek, Marina Lamplough, Megan Meltzer, Sophie Oldershaw.
