Shakhtar Donetsk chief Darijo Srna insists Mykhaylo Mudryk will come good for Chelsea.
Srna oversaw the 100m sale of Mudryk last month.
So far, the Ukraine international has struggled to make a major impact in action for Chelsea.
Srna told Tribuna: Misha will be one of the main players there.
"He showed it in 30 minutes with Liverpool. He is not ready yet, but he is a professional. He just needs patience."