World men's number one Jannik Sinner has been cleared of fault or negligence by an independent tribunal after failing two drug tests in March, the International Tennis Integrity Authority (ITIA) said on Tuesday.
The tribunal accepted Sinner's explanation that the anabolic agent clostebol entered his system from a member of his support team through massages and sports therapy, the ITIA said in a statement.
The team member had been applying an over-the-counter spray containing clostebol to their own skin to treat a small wound, the ITIA added.
"After each positive test, a provisional suspension was applied. On both occasions, Sinner successfully appealed the provisional suspension and so has been able to continue playing," the statement said.
The decision is subject to appeal by the World Anti-Doping Agency (WADA) and the Italian Anti-Doping Agency (NADO Italia), the statement added.
Sinner, who won the Cincinnati Open on Monday, said the independent tribunal had cleared him in April after he fully cooperated in the ITIA's investigation.
"I will now put this challenging and deeply unfortunate period behind me," he said in a statement, adding that the amount of clostebol found in his system was less than a billionth of a gram.
"I will continue to do everything I can to ensure I continue to comply with the ITIA's anti-doping programme and I have a team around me that are meticulous in their own compliance," he added.
The ATP said they were encouraged by the ruling.
"This has been a challenging matter for Jannik and his team, and underscores the need for players and their entourages to take utmost care in the use of products or treatments. Integrity is paramount in our sport," they said in a statement.
Australian Open champion Sinner will play in the US Open later this month, with the main draw starting on August 26.