(REUTERS) - Chinese swimmer Sun Yang has had his eight-year ban for doping violations referred back to the Court of Arbitration for Sport (CAS) after an appeal to a Swiss court, the World Anti-Doping Agency (Wada) said.
The decision could potentially clear the way for him to compete at next year's delayed Tokyo Olympics, depending on when the case is heard.
Sun was banned for eight years by the CAS in February after it accepted an appeal from Wada against a decision by swimming body Fina to clear him of wrongdoing for his conduct during a 2018 test.
Sun appealed against that decision and Wada said in a statement late on Wednesday (Dec 23) it had been informed that the Swiss Federal Tribunal had upheld a challenge against the chair of the CAS panel but had not made any comment on the substance of the case.
"Wada will take steps to present its case robustly again when the matter returns to the CAS panel, which will be chaired by a different president," the statement said.
The New York Times reported that Sun's lawyers had successfully argued to the tribunal that the head of the CAS panel had made public comments that expressed anti-Chinese sentiments.
The tribunal was not immediately available for comment when contacted by Reuters.
Sun, the reigning world and Olympic champion in 200m freestyle, was banned after he and members of his entourage were found to have smashed vials containing blood samples taken at an out-of-competition test in September 2018.
He has questioned the credentials and identity of the testers and has constantly proclaimed his innocence.
The 29-year-old, who won two gold medals at the 2012 London Games and another at Rio de Janeiro in 2016, is a controversial figure in the sport.
He served a three-month doping suspension in 2014 for taking the stimulant trimetazidine, which he said he took to treat a heart condition, while Australian swimmer Mack Horton openly called him a drug cheat at the 2016 Rio Olympics.
Horton refused to share the podium with Sun at the 2019 world championships in South Korea, a move that was applauded by other swimmers but condemned by Fina.
Swimming Australia said it and Horton had no comment on the decision.
Official reaction in China was muted early on Thursday (Dec 24), although the news managed to get into the top-20 trending topics on China's Weibo, a Twitter-like social media platform.
Most users supported the Swiss court's decision to refer his case back to CAS, although many held out little hope of a reversal of the original result.
"The overturn of the case is due to procedural violations, not because of factual flaws," one user wrote.
"The case will be heard by the CAS once more, it is unlikely to reverse the result."