(Vaughn Ridley/Getty Images)

Simona Halep has been provisionally suspended from tennis after testing positive for roxadustat, a banned substance, at the US Open in August.

In a statement, Halep called it “the biggest shock of my life.”

“Today begins the hardest match of my life: a fight for the truth,” she wrote. “I have been notified that I have tested positive for a substance called Roxadustat in an extremely low quantity.”

Roxadustat is a drug that increases the production of oxygen-carrying red blood cells. It’s usually used to treat anemia, which is caused by chronic kidney disease, and is taken by mouth.

In a statement, the International Tennis Integrity Agency said that Halep had requested that her second drug sample be tested. That second sample confirmed the finding of the A sample.

The two-time Grand Slam champion is unable to compete as a result.

She had previously announced in September that she had undergone nose surgery to improve her breathing and would not continue to compete in the 2022 season.

Halep is the highest-profile player to fail a drug test since Maria Sharapova in 2016.

“Throughout my whole career, the idea of cheating never even crossed my mind once, as it is totally against all the values I have been educated with,” Halep continued in her statement.

“Facing such an unfair situation, I feel completely confused and betrayed. I will fight until the end to prove that I never knowingly took any prohibited substance and I have faith that sooner or later, the truth will come out.”

Halep began to work with Serena Williams’ longtime coach Patrick Mouratoglou earlier this season.