Although Mancini has refused to elaborate on the reason behind the "stupid" injury they will keep record-signing Sergio Aguero out of tomorrow's encounter with Sunderland, he has admitted to having no idea when the South American will be fit to return.
Reports in Argentina suggest Aguero has suffered a severely blistered foot after the player's skin reacted to a spray used by City's medical staff to treat a knock he suffered in the recent win over Chelsea.
Carlos Tevez is still not considered fit enough to start either, which leaves only Edin Dzeko, who has scored just five times in his last 25 appearances and none in his last six, and the enigmatic Balotelli as Mancini's only other forward options.
So, whilst Balotelli looks set to be handed an increased role in City's championship challenge, Mancini knows he cannot rely on the Italy forward.
"I don't trust Mario. No-one trusts Mario," said Mancini. "He is a top player. He can do everything. He can score two goals against Arsenal next week. But he can also take a red card.
"Until now he did well and in the last eight games he could be important for us. But trust him? Never."
Not even to remain in England when he is given a couple of days off, as was the case this week when he mysteriously appeared at the announcement of Inter Milan's new coach.
"I can't put him in his house for two days," said Mancini. "Probably the moment will arrive when he will know what he should do when he has two days off. I hope he will grow out of it because he needs to know this is his job. He needs to work and rest. But he is young."
As Mancini spoke around Aguero's injury, it was tempting to think Balotelli might have had something to do with it.
"I am really disappointed for what happened last week," said Mancini. "I am more than really disappointed. It is impossible that we can lose a player for a stupid situation. I will tell you what happened when the season has finished. It was not at home, it was here, but it was not another player.
"He can't play with this injury for a week, 10 days, two weeks? I don't know. For us it is a big problem because we lost Sergio against Stoke and tomorrow he can't play. We hope we can recover him for Arsenal but I don't know if it is possible. I hope it won't be weeks."
Mancini has apologised to Stoke counterpart Tony Pulis for not shaking his hand last week. Mancini said: "I spoke with Tony Pulis. When I turned he had gone to the dressing room but I spoke with him by telephone. There is no problem, I said sorry.
'I was angry because we didn't win the game, not with Tony. I was near the pitch because I wanted to speak with the referee. When I turned, Tony was just inside the dressing room.
"I went to the dressing room, after the game I went to Italy - I didn't meet him. I explained when I called him."