Mancini recalled Balotelli from a four-year international exile last May and has been a champion of the enigmatic forward throughout his career, coaching him at Inter before making him a big-money signing at Manchester City.
However, he failed to find the net in 10 matches for Nice earlier this season amid a breakdown in relations with head coach Patrick Vieira – a former team-mate during his younger days at City and Inter.
And Mancini thinks there is still work to do until he feels he can rely on his old protege.
"Mario is not yet in the best condition to play in the national team," he told a news conference at Coverciano on Monday, where his squad gathered for the qualifiers against Finland and Liechtenstein.
"He has definitely improved but from him, we expect a lot. He starts to have some experience, he is at the peak of his maturation. It will take some time."
#Mancini: "#ItalyFinland is the first game which makes it the most difficult one. I want to see the right approach with a team that is positive and attacks but one that can also endure if needed."#VivoAzzurro #EuropeanQualifiers #Azzurri pic.twitter.com/IkyeCAi3yP— Italy (@azzurri) March 18, 2019
"[Belotti] is a player like the others who stayed at home. I think he can do better and play for the Azzurri again," Mancini said.
"He was with us at the beginning, now there are others. But he is improving and will be back."
Kean caught the eye with an impressive brace in Juventus' 4-1 win over Udinese this month and takes up the mantle of being a bright young hope in the Italy squad – one once held by Balotelli.
"At his age, he played in the national team, he made goals, he won a lot. Let's hope [Kean] starts like Mario, that is to say very well," Mancini added.
"But then go on. It is clear that Balotelli could have done much more, but he did a good career.
"He plays at a big club where they aim to win things and this helps a lot with a sportsperson's development."