Sydney Thunder all-rounder Nicola Carey got the call up to replace Harris and should reach the Stars squad already in India, before the first warm-up match on Monday 14 March 2016.
Southern Stars team doctor Leanne Hutchison confirmed the news.
“Grace has been diagnosed with DVT and started treatment for the condition. After consultation with external specialists and the medical team at Cricket Australia, the decision was made that it was not medically safe for her to fly and play whilst undergoing treatment," she said.
Shawn Flegler, Women’s National Selection Panel Chairman of Selectors, said it's disappointing for Harris as she's an exciting prospect.
"We were looking forward to seeing her performance during the tournament, but her health and safety comes first.
“Nicola Carey has impressed in the Shooting Stars development squad, as well as during our domestic season, and will give our squad a number of options and added depth with her all-round skills," Flegler said.
The last minute call up will see Carey make her T20I debut armed with fresh form from Sydney Thunder's inaugural Women’s Big Bash League overall win this summer. Carey contributed to the Thunder's feat scoring 168 runs, and taking 16 wickets in 16 matches.
Southern Stars’ T20 World Cup fixture (all are local times in India)
14 March, warm-up match v West Indies, Chennai, 3.30pm
18 March, pool match v South Africa, Nagpur, 7.30pm
21 March, pool match v New Zealand, Nagpur, 3.30pm
24 March, pool match v Sri Lanka, Delhi, 3.30pm
26 March pool match v Ireland, Delhi, 3.30pm
30 March – First semi-final, Delhi, 2.30pm
31 March – Second semi-final, Mumbai, 2.30pm
3 April – Final, Kolkata, 2.30pm