Kemp was given her international debut in the summer and soon made her mark against India by becoming the youngest England player, male or female, to make a T20I half-century. She went on to be named the Women's Young Player of the Year by both the PCA and the Cricket Writers' Club, and was recently handed her first England central contract.
Although the ECB said in a statement that there is no specific timeframe for Kemp's recovery, she has already been ruled out of the T20 World Cup, which gets underway in South Africa in February.
"After receiving further exploratory scans in the UK, it has been confirmed that England Women and Southern Vipers all-rounder Freya Kemp has sustained a stress fracture in her back," the ECB said.
"Although the timescale of Kemp's return is to be determined, she will not be available for the ICC Women's T20 World Cup in February 2023.
"She will now begin rehabilitation in partnership with the England Women and Southern Vipers medical teams."
Kemp was not involved in any of England's three ODI wins over West Indies prior to her departure, after suffering with back pain from the outset of the trip.