Roberto Mancini suggested he had sanctioned Mario Balotelli's sale to Milan for the good of the player, describing the maverick forward as "like another one of my children" and saying the Italian could become one of the best players in the world when restored to Serie A.

Balotelli is expected to complete his £17m move on Wednesday after a controversial two and a half years at City, patience having snapped at his antics on and off the pitch. The 22-year-old clashed regularly with Mancini during his time at the Etihad Stadium, not least on the training pitch on 3 January when they were photographed grappling with each other after an altercation. But the manager insisted the forward's departure had proved emotional for him and his squad.

"We are all so sad because Mario was an important player for us," said Mancini in the wake of the goalless draw at Queens Park Rangers. "With Mario we won the Premier League and the FA Cup in two years. He's a fantastic player but, for him, this could be an important chance to go back to Italy and play for a big club in Milan. It will be a good chance for him to stay with his family, to play for Milan. I think he can improve and I'm happy he will become one of the best players in the world.

"We talked. The club asked me what's best for me. I spoke with Mario and I think he wanted this. After three years in England, to go back to Italy will be good for him. We love Mario and he deserves to have this chance. For me, Mario was like another one of my children. I gave him his start in Serie A with me at 17 [with Internazionale]. You can be upset with him sometimes but afterwards he's a lovely lad. I've invested a lot of time with all the players. With Mario, maybe more.

"But I think that Mario is in the history of the club because we won three trophies in two and a half years and he scored important goals in big matches like Manchester United away. He did very well. All the players [will miss him]. When he left the hotel, they were really sad. Mario is a good guy. He lived with us for three years."

City do not envisage replacing the out-going forward, with Mancini – who did not rule out working with the player again in the future – admitting it constituted a risk on one level to sanction the departure of one of their quartet of forwards.

"It was a difficult decision because I've lost one striker, an important striker," said the Italian. "He could have been important in the next 14 games. But it's important for Mario to go back to Italy. Saying goodbye was emotional, but it's normal. When I say that I love Mario, and all his team-mates love him, it's true."