"Further to many medical exams done, it shows that I have a small tear in my calf and I will need more time to recover," Jabeur announced.

"I am sad to announce that I won't be able to compete and defend my title this year."

Jabeur, fourth in the WTA rankings, pulled out of her semi-final against reigning French and US Open champion Iga Swiatek at the Stuttgart Open on Saturday with a calf problem.