Former World Anti-Doping Agency president Dick Pound has accused Maria Sharapova of being "reckless beyond description" for failing a drugs test.
The five-time Grand Slam champion shocked the world on Monday evening when announcing that she had tested positive for the use of recently-banned substance meldonium earlier this year.
Sharapova claimed that she had been taking the substance for the past 10 years for health reasons, but as of January 1 it was officially placed on the banned list.
Some ex-pros have come to the defence of the iconic Russian athlete, but Pound - who was head of WADA for eight years up until 2007 - believes that the blame lies solely with the 28-year-old.
"You are taking something on a list, which you have known about for four months," he told BBC Sport. "I am sorry, that is a big mistake - of course she should have known.
"She is taking something that is not generally permitted in her country of residence (USA) for medical purposes, so she says, so there must be a doctor following this.
"Anytime there is a change to the list, notice is given on September 30 prior to the change. You have October, November, December to get off what you are doing. All the tennis players were given notification of it and she has a medical team somewhere. That is reckless beyond description."
Sharapova, who faces a four-year ban after making the shock admission, is expected to return to the sport rather than retire.
