Australian swimmer Shayna Jack, a member of the world record-breaking 4x100m freestyle relay team, on Monday had her doping ban reduced to two years by the Court of Arbitration for Sport with the suspension ending days before the Tokyo Olympics.
Jack was banned by Swimming Australia for four years after testing positive for the muscle growth agent ligandrol in an out-of-competition test in June 2019.
The freestyle specialist claimed it entered her system by contamination and has fought to clear her name.
Lausanne-based CAS, sport's highest court, concluded that "on the balance of probabilities" Jack "did not intentionally ingest ligandrol" and reduced her ban to two years dating from July 12, 2019.
That means that she could, in theory, compete in the postponed Olympics that start on July 23, 2021. She would however be ineligible during the qualification process in the preceding months.
Jack said on Instagram that "I will walk a little taller tonight with the fact that this ordeal is finally over".
She said the court had "confirmed in emphatic terms that I did not intentionally, knowingly or recklessly use Ligandrol in any manner".
She added: "There was no evidence produced by my accusers as to how this substance entered my system.
"The anti-doping rules are far from satisfactory and can produce results that are far from fair.
"In my case, I have proven that I have NOT ever cheated, nor used prohibited substances intentionally or knowingly. I will still incur two years out of the sport in which I love."
At the time, the Australian team said the case was "bitterly disappointing and embarrassing."
Days after Jack's case came to light, Australian freestyle swimmer Mack Horton refused to share the medal podium at the world championships with Chinese swimmer Sun Yang, accusing him of doping.
The Chinese swimmer was banned for eight years by CAS in February.