"It is difficult because I lost one important striker and that could be important in the next 14 games," Mancini said.
"But it is important for Mario - to be back in Italy, back with his family and to play for Milan."
Mancini believes Balotelli has done "very well" in his two and a half years with City, although concedes this season has proved more difficult.
He was also quick to deny suggestions the departure was related to difficulties in dealing with the forward.
"No, no, no, not for me," he said. "For me, Mario was like another of my children.
"Mario is this but you can be upset with him sometimes.
"The club told me they had this from Milan. I spoke with Mario and I think he wanted this.
"I think for him after three years in England to come back to Italy will be good for him."