The most marketable female athlete in the world, the fallout from that failed test has affected Sharapova's credibility as an endorser -- and jeopardized some of her most lucrative deals.

However, it could have been worse, according to her latest ratings on an independent index that measures consumer perceptions of celebrities in the U.S.

Sharapova's decision to go public for testing positive for the heart drug meldonium has limited some of the damage and means she could yet bounce back, says Matt Delzell -- managing director of The Marketing Arm's celebrity talent group, which launched the Celebrity DBI in 2006.

Her levels on consumer trust and credibility as an endorser dropped "tremendously," Delzell told CNN, yet her appeal stayed the same following her admission.

Sharapova said in a quickly-arranged news conference in Los Angeles on March 7 she had flunked the test for meldonium, claiming she'd been taking it since 2006 for a number of health issues. According to Sharapova, she didn't realize meldonium was added to the banned list in 2016. She could be suspended for up to four years.

A global star since she won Wimbledon aged 17, Sharapova has been ranked the world's best-paid female athlete for the past 11 years by Forbes, which estimated she's made $285 million in on-and-off court earnings.

Guided by IMG since she was a teenager, Sharapova has been sponsored by some of the world's biggest companies, including Nike, Porsche and Evian, while she started her own candy brand, Sugarpova, in 2012.

Within a day of her shock statement, the former top-ranked Russian's deals with Nike and Porsche had been put on hold while Swiss luxury watch maker Tag Heuer decided not to renew its contract. Racket manufacturer Head took the opposite tack, saying it plans to extend her contract.

The Celebrity DBI looks at eight different attributes that marketers use to make decisions on which celebrities to pick to sell products.

In a measurement on credibility as an endorser, Sharapova dropped to 2,799th -- or the bottom 25% -- on March 11 from 787th -- or the top 20% -- the month before.

That puts her level with actress Demi Moore and well behind leader Joanna Gaines, a home designer who presents U.S. DIY television show "Fixer Upper" with husband Chip. Former NBA star Michael Jordan is in second place.

Sharapova's trust score also plunged. While she was ranked 1,084th -- or inside the top 25% -- of 3,900 celebrities on consumer trust in February, she fell to 2,645th -- or the bottom 30% -- on trust on March 11. She's now on par with singer Rihanna and actor Jack Nicholson. Gaines also leads the trust category.

Lower scores on both trust and endorsement are "historically accurate," Delzell said, with celebrities involved in some sort of controversy or scandal in the past.

What surprised him is Sharapova's appeal score. She's still liked by more than 84% of U.S. consumers, compared to 88% last month. Her awareness score also remained flat, at around 70%.

"Overall, not as bad as it could have been but certainly pretty negative," Delzell said. "But staying flat on her appeal score I would consider a silver lining. She mitigated even more of a downfall by coming out and admitting it, owning it, apologizing for it and explaining herself. All of that helped lessen the blow."

Admitting her error instead of waiting for an announcement from tennis officials might help to reduce any suspension she receives, a prominent sports lawyer told CNN in March.

A drop in Sharapova's trust levels would be an issue if she was sponsored by a bank or an insurer, which she isn't.

"If you are Nike, which is a fashion apparel brand, most of the time you will care about performance on the court," Delzell said, rather than focusing on trust.

Chocolate launch

Sharapova's popularity was one of the main reasons behind the decision by U.S. chocolate maker Baron Chocolatier to go ahead with the production and launch of a high-end line under the Sugarpova brand this May.

The company said it was "flooded" with about 400 comments on its various social media outlets after a March 12 piece in UK newspaper The Guardian explaining why it was standing by Sharapova.

"The mix of positive-very negative comments was 70% positive or supportive and 30% negative and non-supportive of our stance," said Christopher Mattina, managing director of Baron Chocolatier, which is based in Vernon Hills, Illinois.

Mattina, who said Sharapova herself informed him of the positive test a few days before the press conference, called the 28-year-old "someone of high integrity" who had made "a mistake."

The chocolate bars, ranging from $3.99 to $4.99 per bar, will be launched on May 15 in Europe and on May 26 in the U.S.

Although Sharapova will be involved with the launch, Mattina said he wasn't sure in which way as that depends on her hearing with the International Tennis Federation "in the next three to four weeks."

Depending on that outcome, can Sharapova bounce back from this?

"Yes she can," Delzell said, explaining that "making a sincere apology," "staying out of the limelight" and then playing well will all be important.

"If she gets banned less than a year or so, that would be good for her because she can then get back on the court. Winning solves a lot of problems."

(CNN)