Nike has suspended its contract with tennis star Maria Sharapova after the former world number one said she had failed a drugs test at the Australian Open in January.
Ms Sharapova — easily the world’s best paid female athlete — announced on Monday she had tested positive for meldonium, an endurance-enhancing drug.
“I did fail the test and take full responsibility for it,” said the 28-year-old Russian, who stormed on to the world stage in 2004 when she won Wimbledon aged 17.
“I know that with this, I face consequences,” she added. “I don’t want to end my career this way. I really hope that I will be given another chance to play this game.”
Ms Sharapova said she had been taking the medicine, under its alternative name mildronate, for the past 10 years for health reasons, and that she had not known the substance had been banned.
Meldonium was added on January 1 to the list of substances banned by the International Tennis Federation, world tennis’s governing body, following a decision last September.
The ITF said it had suspended Ms Sharapova with effect Saturday March 12, pending “determination” of the case.
Nike said it was “saddened and surprised” by the news.
“We have decided to suspend our relationship with Maria while the investigation continues,” it said in a statement.
Ms Sharapova has long been considered sport’s biggest female brand, topping Forbes’ ranking of the world’s highest-paid female athletes in each of the past 11 years.
Nike was one of many companies, including Porsche, Evian and Tag Heuer, paying her a combined total of more than $20m in annual endorsements — a figure that dwarfs her 2015 prize money by a multiple of six.
The deals gave the companies image rights for billboards and magazines and also access to Ms Sharapova’s vast presence on social media. The tennis player has more than 15m followers on Facebook and 2m on Twitter, in addition to her personal web app.
John Haggerty, Ms Sharapova’s lawyer, said she had been unaware the substance was banned at the time of the Melbourne tournament, where she lost in the quarter-finals to world number one Serena Williams.
“We are attempting to have a conversation with ITF up front because we think there is a laundry list of extremely mitigating circumstances that once taken into consideration would result in a dramatically reducing any sanction that they might want to impose on Maria,” he told the US magazine Sports Illustrated.
Ms Sharapova is not the first sports star to be dropped by Nike in recent weeks.
The sportswear group ended its contract with Philippine boxing hero Manny Pacquiao last month after he described same-sex couples as “worse than animals”.
Nike said the comments were “abhorrent”.