The Cleveland Cavaliers forward was the top pick in this year's Draft, but has no points from his first four games in the NBA.
The head coach told The AP: "I look at it as he's a guy that can grow slowly into his role with us and that's the exciting part of it. I just want him to keep going out there and playing, and if you can take advantage of your opponent on either end of the floor, go ahead and do it.
"Defensively, he's been better than what I thought. I actually thought he was going to struggle defensively, bad. But he's picked up on the concepts and he's been tougher and stronger than what I expected.
"At the end of the day, and I've seen it with my own eyes, he can score. He can score from all three levels and once he figures out how hard he has to play offensively in order for it to happen on a possession by possession occurrence, he'll be good."
The Cavaliers face the Milwaukee Bucks later today.