Chelsea have confirmed that they had been contacted by the FA after the Ukrainian winger provided an "adverse finding in a routine urine test".

Mudryk has denied knowingly using a banned substance and the Blues have said that they will work to find out what has caused the positive test.

The player wrote on Instagram: "This has come as a complete shock as I have never knowingly used any banned substances or broken any rules, and am working closely with my team to investigate how this could have happened.

"I know that I have not done anything wrong and remain hopeful that I will be back on the pitch soon."

A statement from Chelsea added: "Chelsea Football Club can confirm the Football Association recently contacted our player Mykhailo Mudryk concerning an adverse finding in a routine urine test.

"Both the Club and Mykhailo fully support The FA’s testing programme and all our players, including Mykhailo, are regularly tested. Mykhailo has confirmed categorically that he has never knowingly used any banned substances. Both Mykhailo and the Club will now work with the relevant authorities to establish what has caused the adverse finding.

"The Club will not be commenting any further."

It is unclear what substance was found in Mudryk's test or whether the winger has been handed a provisional suspension from football.

Mudryk last played for Chelsea on November 28 and has missed the club's past five games in all competitions.

Manager Enzo Maresca has stated that the player's absence has been due to illness.