Maria Sharapova's management team have issued a statement claiming that the tennis star "makes no excuses" for "missing" five warnings that meldonium was about to be banned by the World Anti-Doping Agency.
The five-time Grand Slam champion revealed on Monday that she failed a drug test after losing to Serena Williams at the Australian Open in January.
The Russian sportswoman told reporters that she has been taking the prescribed medicine for the last 10 years, but declined to click on a link to WADA's updated banned substances list for 2016 via an email on December 22.
Meldonium was included in the list of WADA's performance-enhancing drugs at the beginning of the year, and The Times reports that all tennis players were warned five times in total last year that the substance was due to be banned.
Via The New York Times, Sharapova's camp released a statement, which read: "Whether it was one notice of some kind or more than one, Maria has already acknowledged she should have known. She makes no excuses for missing it."
The 28-year-old will be provisionally suspended from March 12 and faces a four-year ban.