Maria Sharapova hit out at tennis authorities on Friday for failing to warn her that a drug she had been taking had become a banned substance.
Sharapova, a five-times Grand Slam champion, had an initial two-year suspension by the International Tennis Federation (ITF) reduced to 15 months after she tested positive at the 2016 Australian Open for meldonium.
This was a medication the Russian had been taking when it was within the rules but which was later reclassified as a prohibited drug.
"Why didn't someone come up to me and have a private conversation, just an official to an athlete, which would have taken care of the confidentiality problem they talked about later?" Sharapova told The Times.
However, she did accept she had become "complacent", saying she was responsible for failing the drug test.
"Ultimately the fault was mine," she added. "I had been getting clearance on everything I was taking for seven years and I became complacent."
Meldonium was added to the World Anti-Doping Agency list of banned substances at the start 2016 after increasing evidence that it enhanced performance.
Sharapova is set to make her return to competitive tennis at the WTA Stuttgart Grand Prix, which starts on April 24.