However, Ranieri insists the summer signing from Girona has still much to improve in his game.
He said ahead of Sunday's clash with Fiorentina at the Olimpico: "I still believe in him. He's a player who has made significant progress. It's not a bad purchase. There are those who adapt sooner and those who adapt later.
"You remember (Edin) Dzeko. He brought us many important points. As a first year he's positive. He has to improve because he has the means and the ability to do so."
Asked if Dovbyk could be sold this summer, Ranieri was reluctant to make a call.
He also said, "I don't like to talk about these things. I like to talk about what we would like to achieve this year. They can distract concentration. What comes after the Championship, we will talk about it at the end of the Championship.
"It applies to him, but it applies to everyone."