The 21-year-old Bulgarian fell awkwardly after a challenge with Patrice Eva and was stretchered off after just five minutes following his surprise inclusion in the starting line-up.
Hospital scans showed damage to the cruciate ligaments and specialists believe it will be the New Year before the striker returns to training.
Bojinov, who has only played 47 minutes football since his £6m switch from Fiorentina last month, will return to Italy for treatment.
"I will have a surgery in Rome," he said. "It will be done by the doctor who operated on Italy's Francesco Totti. He (the doctor) is a friend of my agent and we decided to choose him."
Decision
City chief Sven-Goran Eriksson will now have to decide whether to bolster his strikerforce with another new face and shelve his search for an experienced goalkeeper.
At the very least, Bojinov's injury may mean the postponement of a possible return to his homeland for Italian international Bernardo Corradi who scored prolifically in pre-season but has yet to make the bench this term.
Eriksson, who has only 10 days of the transfer window to do any deal and a dwindling budget after spending nearly £40m and putting half that much again on the wage bill, also has l Georgios Samaras, Darius Vassell and Paul Dickov to back up £9m man Rolando Bianchi and Belgian Emile Mpenza.
He knows that top strikers come at a premium and may feel that he has enough firepower to get him to the January window when Bojinov's progress can be re-assessed.
If he doesn't, the avenues open to him could include an attempt to hijack Everton's bid for Yakubu or a bid to tempt Guti from Real Madrid.
What do you think City should do? Have your say.
Tweet
David (21/08/2007 at 08:51)
sven needs to act quickly if he wants the yak, before everton snap him up.
i'd try corradi for the arsenal game, if he cuts it, maybe move for a lower league striker on loan til jan with the option to buy. eastwood would have been good before he moved to wolves...
sharp maybe?
give it a go sven