Thunder's grand final hero pulls out of WBBL|07

The Sydney Thunder have been dealt a significant blow just weeks out from the start of the Weber WBBL season, with star South Africa fast bowler Shabnim Ismail forced to withdraw from the competition due to injury.

Ismail, one of the world’s quickest bowlers, had penned a new deal with the reigning champions and had been due to arrive in Australia this week to commence her quarantine period.

But she was forced to return home to South Africa after sustaining a knee injury during the Proteas tour of the West Indies.

The 32-year-old was a force with the ball through the Thunder’s successful WBBL|06 campaign, forming a formidable new-ball pairing with Sammy-Jo Johnson.

She was named player of the match for her fiery spell in the final against the Melbourne Stars, where she took 2-12 to upset the title favourites.

"She took a bad knock and unfortunately Shabnim won’t be able to play in this season’s WBBL competition," Thunder coach Trevor Griffin said.

"It’s terrible news because she’s been an important member of Sydney Thunder over the last couple of seasons.

"She showed her class in the final against the Melbourne Stars at North Sydney Oval last year."

With the season to start on October 14 in Hobart, the Thunder now need to move quickly to secure a replacement fast bowler and will likely cast their eye over talent in the United Kingdom, New Zealand and the touring India squad.

The news comes a day after the Thunder confirmed the signings of star India pair Smriti Mandhana and Deepti Sharma.

Opener Mandhana slots into the place vacated by England opener Tammy Beaumont, while Deepti’s off-spin and skill in the middle-order makes her an ideal replacement for England’s Heather Knight.

Neither England player was re-contracted for WBBL|07 due to a conflicting international tour of Pakistan, which has since been cancelled.

Changes to overseas personnel aside, the Thunder have largely kept their championship squad intact, with Rachel Trenaman the only local departure, replaced by former Hurricanes batter Corinne Hall.

With the first 20 matches of the season moved to Tasmania, the Thunder’s Sydney and Canberra-based players flew to Hobart last Thursday to commence a fortnight of hotel quarantine, while Melbourne-based Sam Bates travelled with the Victoria contingent on Friday.

The Thunder have one local spot left to fill on their list, alongside the overseas vacancy.

Sydney Thunder WBBL|07 squad so far: Rachael Haynes* (c), Sam Bates, Hannah Darlington, Corinne Hall, Sammy-Jo Johnson, Anika Learoyd, Phoebe Litchfield, Smriti Mandhana (Ind), Kate Peterson, Olivia Porter, Deepti Sharma (Ind), Lauren Smith, Tahlia Wilson

In: Smriti Mandhana, Deepti Sharma, Corinne Hall (Hurricanes)

Out: Rachael Trenaman (Hurricanes), Tammy Beaumont, Heather Knight, Shabnim Ismail

WBBL|06 squad members off contract: Saskia Horley

*Australia contracted player