Tennis star Maria Sharapova has a long way to fall.
For a decade the world's highest paid female athlete, her admission that she was first prescribed a now-banned substance in 2006 raises questions whether she has been taking the drug all that time, and whether she disclosed its use.
She was under no obligation to list the drug, meldonium - or mildronate as she knew it - on forms when she provided samples for testing but it could have paved the way for what sports professionals know as a therapeutic use exemption.
Athletes are encouraged to disclose medication for obvious reasons. If she did not reveal her use of meldonium, which she says she was prescribed for health reasons, it seems a remarkable oversight in light of the intense scrutiny of drugs in sport. It would seem too late now for Sharapova to raise the therapeutic option, but it is astonishing that such an elite performer, surrounded by a battery of advisers and lawyers, would be left so exposed.
Clearly the reaction of her major sponsors suggests they want to be some distance from the 28-year-old should things go from bad to worse.
Nike announced it would suspend their relationship with Sharapova until the outcome of the case was known. Swiss watchmaker TAG Heuer put contract renewal talks on hold. Endorsement income is estimated to be worth US$20 million ($30 million) a year to the Russian-born tennis player, who over her career has earned in the order of US$200 million.
A worst-case outcome - a four-year ban - would spell the end of her professional days and a spectacular fall from grace.
The five-times grand slam champion has explained she had been using mildronate and was unaware of the different name and the fact it was on the World Anti-Doping Agency's banned list until she was advised of the positive test from the Australian Open. If she didn't know then someone was asleep at the wheel.
Sharapova says her doctor prescribed the drug 10 years ago after irregular heart tests. The drug makers though say a typical course lasts four to six weeks.
She also maintained she failed to click an email link in a letter from the World Anti-Doping Agency which would have alerted her to the change in the drug's status.
The fact the drug was banned did not come out of the blue. It had been on Wada's 'watch-list' all of last year, which should have rung bells with her retinue. How they missed as many as five warnings about the drug beggars belief.
The athlete faces awkward problems with the drug itself. It is not licensed for sale in the United States, where she lives, and though she says it was not performance-enhancing for her, Wada banned it for that very reason.
Latvian researchers developed the drug for patients with heart conditions brought on by a lack of oxygen in their blood. It has become popular with athletes who use the oxygen-enhancer to improve endurance.
Sharapova is provisionally suspended from tennis as of today. For a superstar and a super-earner, she faces an endurance test of a very different nature as she waits for the game's administrators to deal with the question whether the most bankable player in tennis is a drug cheat.