Athletes who have tested positive for the banned substance meldonium before March 1 could get a reprieve after the World Anti-Doping Agency admitted on Wednesday that it was unable to establish when the drug exits the body. Among the most high-profile athletes who could be affected by this admission is Russian tennis star Maria Sharapova who admitted that she had tested positive for the substance in January.

WADA said there was a lack of clear scientific information about excretion times. "As a result it is difficult to know whether an athlete may have taken the substance before or after January 1, when it became illegal. In these circumstances, WADA considers that there may be grounds for no fault or negligence on the part of the athlete " said WADA, as reported by Reuters.

"The fact that WADA felt compelled to issue this unusual statement now is proof of how poorly they handled issues relating to meldonium in 2015," said Sharapova's lawyer, John Haggerty. "Given the fact that scores of athletes have tested positive for taking what previously was a legal product, it's clear WADA did not handle this properly last year and they’re trying to make up for it now."

WADA's clarification was also welcomed by the Russian Sports Ministry and the Russian Tennis Federation.