Neither the English Football Association (FA), Chelsea, nor Mudryk's lawyers have commented on the information.
Mudryk, 25, has been banned since December 2024, but the FA has never released any details about the suspension.
The BBC has been in contact with CAS, which confirmed Mudryk's appeal: "CAS can confirm that an appeal from Mychajlo Mudryk against the FA was received on 25 February 2026."
According to the BBC, Mudryk failed a doping test in October 2024 with traces of the banned substance meldonium.
Chelsea paid around one billion kronor for Mudryk in early 2023 and his contract with the club extends until 2031.
