The Ukraine international has been provisionally suspended by the Football Association (FA) after a routine urine test provided by Mudryk returned an “adverse finding”.
The 23-year-old, who is unable to play for or train with the club during his suspension, denies knowingly using a banned substance.
Maresca hopes the winger will quickly be absolved of blame.
“We support Mykhailo and trust means that we believe Mykhailo,” said Maresca.
“The club, the coaching staff and all of the people that are inside the training ground – we support and we trust Mykhailo.
“I think he is going to come back but we don’t know when.
But for sure he is going to come back.”
Maresca has spoken to Mudryk since the suspension was made public, while the Professional Footballers’ Association is expected to contact the winger to offer its support.
“Any kind of player that this kind of things happens to, they need support, you would need support and I would need support,” said Maresca.
“It is not about his age or the country that he comes from.”
Mudryk, who signed from Ukrainian club Shakhtar Donetsk in a deal worth up to £89m in 2023, has scored 10 goals in 73 appearances for Chelsea.
He has missed the last five matches in all competitions, with Maresca publicly claiming Mudryk was missing through illness.
Players found to have intentionally taken a banned substance can be banned for up to four years under Fifa guidelines.
