According to the EU’s medicines agency, which approved Roxadustat last year, it stimulates the body to produce more of the natural hormone erythropoietin, or EPO, which has long been a doping product favored by cyclists and distance runners.
During a provisional suspension, a tennis player is ineligible to compete in, or attend, any sanctioned events.
Under the World Anti-Doing Code, Halep faces a ban of up to four years for a positive test for a substance like Roxadustat. Athletes can earn a reduction in their ban if they quickly admit an offense and accept their sanction.
Tennis authorities will handle Halep’s case and any ruling can be challenged by the World Anti-Doping Agency in an appeal to the Court of Arbitration for Sport.
“Today begins the hardest match of my life: a fight for the truth,” Halep wrote Friday.