Maria Sharapova has revealed that she failed a drug test at the Australian Open.
Sharapova, 28, said she has been taking a drug called meldonium for 10 years, that was not originally on the banned substances list.
However, on January 1 the drug was added, and Sharapova confirmed she failed a drug test and received a letter from the International Tennis Federation.
Sharapova took full responsibility for the mistake.
"I've let my fans down, I've let the sport down that I've been playing since the age of four," she said at a press conference in Los Angeles.
"I know that with this I face consequences and I don't want to end my career this way. I really hope I will get the chance to play this game again."
Sharapova said she did not know the ruling had changed on the substance, a drug she had been taking since 2006.
"I received a letter on 22 December from Wada for the changes  and where the tests will be with a link to the changes for 2016 and I did not look at that list.
"I was first given the substance back in 2006. I had several health issues at the time, I was getting sick a lot of the time, I had deficiency in my magnesium, I had irregularities in my scans and I had signs of diabetes."
Meldoniun is used medically to improve blood flow and improves exercise capacity in patients with chronic heart failure.