By top 4 D man he is looking like a no.4 D man, which is different from a no. 3 D man , value is a chunk less, but still valuable. Hamonic is a good example of a no.4 , and yeah , Larsson, the guy Chia traded for an elite winger is another. Call me crazy, but the value assigned to Hamonic is closer to the mark in terms of value. Chia paid for a top pair D man.
So if Juulsen can develop into a strong defensive player and get that 15 points or so then he is a no.4 . If he can break into that 25-30 point area, then he can fill the no.3 slot. See what time does.