The 2023 Wimbledon girls' singles runner-up Nikola Bartunkova has been provisionally suspended for doping.
The Czech 18-year-old returned a positive test for trimetazidine in February and again in March.
Trimetazidine is a metabolic modulator sometimes used as heart medication.
Bartunkova beat world number 21 Dayana Yastremska to secure her first tour victory last year and reached a career-high ranking of 226 in April.
She was beaten by American Clervie Ngounoue in last year's Wimbledon juniors final.