Maria Sharapova has had her multi-million dollar deal with Nike "suspended", by the global megabrand.
It is a further blow for the five-time Grand Slam champion, who has been the highest paid female athlete in the world for the past 11 years.
According to Forbes, she earned nearly US$30 million between June 2014 and June 2015, with around US$23 million of that money coming from endorsements.
Her sponsors include, Nike, Head, Porsche, Evian and Avon.
“We are saddened and surprised by the news about Maria,” Nike said in a statement.
“We have decided to suspend our relationship with Maria while the investigation continues. We will continue to monitor the situation.”