Tennis star Maria Sharapova has lost several major sponsors after admitting that she failed a drug test at the Australian Open.

The former world champion has been the highest-paid female athlete in the world for 11 years in a row, Forbes reported last year. She earned $29.7 million last year — including "$23 million from endorsements and appearances," according to Forbes.

Sharapova told reporters in Los Angeles on Monday that she tested positive for meldonium, which was recently banned. Here's what she said:

"I did fail the test, and I take full responsibility for it. ... It's very important for you to understand that for 10 years, this medicine was not on WADA [World Anti-Doping Agency]'s banned list and I had been legally taking the medicine for the past 10 years. But on Jan. 1, the rules had changed and meldonium became a prohibited substance, which I did not know. ... I was given this medicine by my doctor for several health issues I was having in 2006."

As the Two-Way reported, ITF documents show "meldonium was moved from the 'monitoring program' and added to the 'prohibited list' beginning in 2016." That's because of "evidence of its use by athletes with the intention of enhancing performance."

Nike quickly cut ties with the 28-year-old star. "We are saddened and surprised by the news about Maria Sharapova," the company said in a statement Monday afternoon. "We have decided to suspend our relationship with Maria while the investigation continues. We will continue to monitor the situation." An eight-year contract extension with Nike in 2010, Forbes said, "could be worth as much as $70 million, including royalties."

Likewise, sponsor Porsche said it was "saddened" and told NPR: "Until further details are released and we can analyze the situation, we have chosen to postpone planned activities."

And luxury watchmaker TAG Heuer said Sharapova had been under contract with the company until the end of 2015. "We had been in talks to extend our collaboration. In view of the current situation, the Swiss watch brand has suspended negotiations," a spokesperson told NPR.

Danone, the owner of Evian water, said in a statement to Reuters that it was "surprised" by the positive drug test but stopped short of cutting ties with Sharapova. "Evian has been a partner of Maria Sharapova for many years, and until now, we have maintained a trustworthy professional relationship. ... We will follow closely the development of the investigation."

Nigel Currie, a sponsorship consultant, described Sharapova as a "one-woman marketing machine" in an interview with the AP. "There are lots of male stars in the world, but not many female stars."

As we reported, Sharapova said she hopes the scandal isn't career-ending:

"When Sharapova, who withdrew from this week's BNP Paribas Open at Indian Wells owing to injury, announced her intent to hold a news conference to make an announcement, there was rampant speculation that she would be retiring. She shot down those rumors, saying, 'I know I face consequences and I didn't want to end my career this way. I hope I will be given the chance to play this game again.' "

The Tennis Anti-Doping Programme said in a statement that Sharapova "will be provisionally suspended with effect from 12 March, pending determination of the case."

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