Jovetic ruled out for six months
The shaggy-haired Montenegrin, who will have surgery following the injury in pre-season training, was a key part of the side which made the Champions League last 16 last term.
His loss is a big blow to the Florence club, who now only have Alberto Gilardino available as a recognised frontman given Adrian Mutu is out until October because of a drugs ban.
Fiorentina may now have to enter the transfer market having said on Tuesday that no more deals would be done before the August 29 kick-off after pulling out of an agreement to sign Liverpool left back Emiliano Insua.
Former Catania coach Sinisa Mihajlovic has taken over as Fiorentina boss after Cesare Prandelli left to manage Italy.