The left-arm seamer, who was part of the squad that reached the final of the ICC Women's World Cup in New Zealand in April, experienced discomfort after playing in the Charlotte Edwards Cup and subsequent scans displayed the fracture.
Farrant is set to be out for around six months, with the possibility of returning slightly earlier to regional cricket as a batter. She will be unavailable for England Women’s internationals and The Hundred. The medical teams at England and South East Stars will work together on her rehabilitation.