Tennis star Maria Sharapova announced on Monday that she failed a drug test at the 2016 Australian Open.

Busted Racquet noted that the failed test was for Mildronate, also known as Meldonium, which is a substance that she had taken since 2006. It was added to the list of banned substances in January, but Sharapova did not check the updated list.

"I received an email on 22 December from Wada [World Anti-Doping Agency] about the changes happening to the banned list and you can see prohibited items, and I didn't click on that link," she admitted.

Sharapova, a former World No. 1, added that she did not want to end her tennis career on this note and is hoping she can continue to play. At this point it is not known what discipline she will face for the failed test.

The 28-year-old has been sideline recently with a shoulder injury and last played when she lost to Serena Williams in the quarterfinals at this year’s Australian Open.

Meldonium is a clinically used anti-ischemic drug and can increase an athlete’s endurance.