Former Wimbledon champion Marketa Vondrousova was handed a four-year suspension on Monday for refusing an anti-doping test.
Vondrousova did not submit a sample when notified by a doping control officer during an out-of-competition test attempt at her home in December 2025.
The 26-year-old Czech, who won Wimbledon in 2023, claimed "months of physical and mental stress" affected her decision making, in addition to concerns for her safety.
Writing on Instagram in April, Vondrousova said she was scared when the doping officer approached her door late in the evening "without properly identifying themselves or following protocol.
"In that moment it was about feeling safe, not about avoiding anything."
Players are required to log their whereabouts for an allotted hour each day so that authorities can conduct anti-doping tests outside of competition.
An independent tribunal considered Vondrousova's claims, as well as testimony from the doping control officer who attempted to conduct the test.
The tribunal concluded that the evidence offered "no compelling justification" for the world number 122 to refuse the test.
International Tennis Integrity Agency CEO, Karen Moorhouse said: "We understand that the testing process is uncomfortable, and acknowledge that it is an additional burden for players whose jobs already come with a high level of pressure and scrutiny, but it is essential to protect fair competition.
"Safety and welfare of players and our testers is really important to us. Our testers are well-trained, professional, and the gender of our testing witness always matches the player.
"They carry ID at all times, and players are able to verify their identity in other ways if they are ever unsure."
Vondrousova's suspension will end on June 21, 2030.
CONSIDERING APPEAL
During her ban, the Czech is not allowed to play in, coach at, or attend any events organised or sanctioned by the ITF, WTA, ATP, the Grand Slams, or any national association.
Vondrousova will consider the verdict before deciding whether to appeal to the Court of Arbitration for Sport (CAS).
"Marketa has asked me – and I want to respect her wish – to refrain from commenting on the matter at this stage," Vondrousova's lawyer Jan Exner told AFP.
"Basically when we get the verdict, we will read the explanation and decide on further action, whether we will appeal it or not, but first I want to consult Marketa and I don't want to speculate on further steps.
"I want to respect Marketa's wish and I don't want to go into detail."
Vondrousova, who has won three WTA Tour singles titles, became the first unseeded player to clinch the Wimbledon women's singles title when she defeated Ons Jabeur in straight sets in the final three years ago.
She also reached the French Open final in 2019, losing to Ashleigh Barty, and earned a silver medal in the 2021 Tokyo Olympics.
Vondrousova reached a career high sixth place in the WTA rankings in 2023.
She has played just two matches on the WTA Tour this year, withdrawing from the Adelaide International in January due to a shoulder injury.