The former Manchester City defender, 22, was withdrawn after 30 minutes of the 2-2 draw in Florence, with initial medical tests today confirming damage to his thigh.
Montenegrin striker Jovetic, meanwhile, was expected to miss out against Milan after hurting his thigh against Cagliari, and his ill-fated start yesterday resulted in his withdrawal at half-time.
A statement on the club's official website read: "Fiorentina announce that Stefan Savic has suffered flexor muscle damage to his thigh. At the same time Stefan Jovetic has experienced a recurrence of his recent thigh muscle injury. Both players will be subjected to diagnostic tests tomorrow."
Jovetic, 23, has scored 12 goals in 26 league appearances this season while Savic has established a solid partnership with Serbian Nenad Tomovic, who was sent off yesterday, since leaving City last summer.