Manager Roberto Mancini confirmed that if Balotelli's registration is sealed by midnight on Wednesday then Santa Cruz will exit City's Europa League squad.
And that could be the beginning of the end for the Paraguay international, with City about to start their European campaign in Romania against Timisoara on Thursday.
Balotelli still faces competition for a place in the starting line-up with Carlos Tevez, Emmanuel Adebayor and Robinho all on board.
But the 20-year-old is keen to mix it right away after arriving from Inter Milan last week when he sealed a five-year deal.
He said: "I came here to play all the games and I will do my best to be in the team every week. Of course this is time to mature. But mistakes can always occur. I'm still young, I am not old."
On the day Balotelli was officially unveiled to the media, James Milner moved closer to sealing his protracted move from Aston Villa. Stephen Ireland is due to go the other way, and that part-exchange deal, worth around ¦pound;26million, could be finalised on Wednesday.
And on another frantic day of transfer activity at the club, Bellamy stepped down a division to join hometown team Cardiff on a season-long loan.
Bellamy and Ireland may not be the last two out of the Eastlands revolving door, as goalkeeper Shay Given could also be leaving after being unhappy at losing his place to Joe Hart.
Mancini said: "I hope he (Given) will stay with us because we are in four competitions. But I respect his wishes if he wants to leave."
Source: PA
Source: PA