Allegri has given his tacit approval to a January bid for Balotelli, a self-confessed Rossoneri fan who has done little to play down reports he would like to return to the San Siro.
A winter move seems out of the question, though the 20-year-old recently only committed himself to Eastlands till the end of the season.
Milan were tipped to sign former City striker Rolando Bianchi from Torino as a stopgap in January before making a Balotelli bid in the summer, but Allegri insists he wants a superstar or no one this winter.
"In January the priority is a great forward," said the coach, who is short after a long-term injury to Pippo Inzaghi and continuing problems with Alexandre Pato. "I agree with (Milan chief executive Adriano) Galliani: either we find a top striker or we might as well stay as we are."