The Football Association confirmed on Wednesday that Mykhailo Mudryk of Chelsea FC has been handed a four-year ban for breaching anti-doping regulations, according to the Daily Mail.
The sanction represents the harshest penalty available for such an offence.
The Ukrainian international has opted to challenge the ruling at the Court of Arbitration for Sport.
The 25-year-old formally lodged his appeal on February 25, although a hearing date has not yet been fixed.
He has not made an appearance for Chelsea since November 28, 2024.
The Ukrainian winger joined the London side from Shakhtar Donetsk in 2023 in a deal worth £88 million.
His current contract with the English Premier League giants runs through to 2030.
