The former Milan striker says the Portuguese star must improve mentally if he wants to reach the very top.
"Leao shows great qualities and enormous potential to improve what he already does well," Incocciati told Football Presse.
"But it is not enough to give the impression of being good."
Incocciati believes the real issue is psychological.
"He must improve the psychological aspect. He has to grow a lot in managing his emotions."
And he delivered a blunt verdict on Leao's inconsistency.
"In football you cannot play one good match and then three bad ones."
"If you want to be defined as a top player, every match must be played at a high level."
That, Incocciati insists, is where Leao has fallen short.
"He has not yet shown that he can do this."
However, there is hope.
With Allegri back at the helm, Incocciati believes the winger could finally unlock his full potential.
"We hope that with Allegri he can show his maximum potential. We will see."
The talent is there.
Now the mentality must follow.