Maria Sharapova announced this week that she failed a drug test in January and could face harsh consequences that may effectively end her tennis career.

The 28-year old athlete says she has been taking a drug called meldonium, which helps increase blood flow and energy for the user. The substance has been banned by the WADA, but Sharapova says she didn’t know it had been added to the list of prohibited drugs because she didn’t fully read an email announcement.

“I know that with this, I face consequences. I don’t want to end my career this way, and I really hope I will be given another chance to play this game…I take great responsibility and professionalism in my job, and I made a huge mistake. I let my fans down. I let the sport down that I’ve been playing since the age of 4, that I love so deeply,” Maria said.

Maria Sharapova has reportedly been taking the drug for a number of years due to irregular heart tests, but it’s unclear at this point whether she will be suspended, which could affect her ability to participate in the Olympics.

“I understand the drug is sold particularly in Eastern Europe. You can almost get it over the counter. For stronger versions, you might need a prescription. There has been a whole rash of these cases since the 1st of January when it appeared on the banned list. This might not be happening if athletes would be taking more care of the things that are on the list,” said WADA President Craig Reedie.

It’s possible that an investigation will prove that Sharapova was unaware that the drug was banned, and her career won’t be in jeopardy. However, failed drug tests can result in up to four years of suspension depending on the player and what the circumstances are.