I don't think it will super clearcut... We'll see lots of rotation again.
The thing is, Mandzu is a player that suits Dybala's playing style better. Whereas Morata is more of a hybrid CF-SS... It's why his assist numbers were so high, and why it was so frequent that Allegri sub'd Morata on for Dybala, and started Mandzu-Morata together at times both in the 4-3-3 early in the season and the 3-5-2 later. Mandzu-Morata, and Morata-Zaza with Morata playing off a main CF always looked quite good.
Morata has excellent SS characteristics, his passing and vision are surprisingly good. Whereas his goalscoring instincts aren't really all that good yet, at least not in Serie A with the defensive style and packed box. He's an interesting forward that way. He's actually a very good SS in Serie A matches (and a mediocre CF), but an excellent CF in Champion's League.