ROME (AP) — Time is running out for appeals to be filed in the case that exonerated freshly-crowned U.S. Open champion Jannik Sinner from doping .

The World Anti-Doping Agency (WADA) and Nado Italia, Italy’s anti-doping agency, likely have only one more day to challenge the decision announced by the International Tennis Integrity Agency (ITIA) on Aug. 20. There is a 21-day window to appeal that started when the parties received the decision.

Any appeal would be filed to the Switzerland-based Court of Arbitration for Sport (CAS). Sinner tested positive twice for an anabolic steroid in March but was not suspended because the ITIA determined the banned performance-enhancer entered his system unintentionally through a massage from his physiotherapist. The doping case was kept secret until last month’s announcement and the top-ranked Sinner went on to beat Taylor Fritz in the U.

S. Open final on Sunday. An appeal could jeopardize his U.

S. Open title but Sinner and his legal team have provided detailed scientific evidence to show that his explanation is credible. Sinner said after winning his second Grand Slam title that the months before his case was resolved were not easy.

“It was very difficult for me to enjoy in certain moments,” he said, “so whoever knows me better, they know that something was wrong. But during this tournament, slowly I restarted to feel a little bit more how I am as a person.” While other players have expressed concern with how Sinner's case was.