Chelsea forward Mykhailo Mudryk says he is in 'complete shock' after being provisionally suspended by the Football Association (FA) after being notified of a positive drug test.
The 23-year-old, who joined the Blues from Shakhtar Donetsk last year, hasn't featured for Enzo Maresca's side since the UEFA Conference League win over Bundesliga outfit Heidenheim at the end of November - missing the last five outings.
Mudryk has denied any wrongdoing and has argued that he has "never knowingly used any banned substances or broken any rules".
Chelsea have confirmed that there was adverse finding in a routine urine sample from the Ukrainian. However, the club have stated that they will not comment further on the investigation as they support the FA's testing programme and will work with the relevant authorities to establish what has caused the adverse finding.
"I can confirm that I have been notified that a sample I provided to The FA contained a banned substance," he wrote in a post 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. I cannot say any more now due to the confidentiality of the process, but I will as soon as I can."
Chelsea return to competitive action on Thursday when they host Shamrock Rovers in their sixth Conference League outing before heading to Merseyside to take on Everton in the Premier League. Following a run of five straight wins, Maresca's side sit two points behind league leaders Liverpool.