Icardi has not featured in any of Inter's last three matches with an apparent knee injury amid continued speculation over his future at the club after he was stripped of the captaincy.
Inter have reportedly offered Icardi a new four-year contract worth €6.5 million per season, but he will not be re-joining his team-mates for the trip to the Artemio Franchi, with Keita Balde Diao also still unavailable.
Speaking at a pre-match media conference, coach Luciano Spalletti said: "I hope to have Icardi and Keita back as soon as possible.
"It's unlikely for a team like Inter to depend on just one player as, if we did, then we wouldn't be a top-level side. There are others who can make the difference and allow us to stay in the top spots of the table.
"The team has clearly done better over the last few games and sorted out some things that had not been working well, but at the same time our lead over the chasing pack has been reduced and we've got to keep winning.
"There are many reasons for the improvements. On an individual level, we must give our all to get positive answers.
| #Spalletti: "@KeitaBalde is improving but we still have to wait a few days. I hope that @MauroIcardi will be back soon. Other players can help with goals. @joaome17 needs to score more while @vecino and #Brozovic know where the goal is."— Inter (@Inter_en) February 23, 2019
"We need to get some players back for the forward line, as our numbers are limited there at the moment and I'd prefer to have more options to rotate the squad."
Inter are third in Serie A, a point ahead of city rivals AC Milan, but face a Fiorentina side unbeaten in eight games in all competitions and boosted by the loan signing of Luis Muriel, who has scored three goals in five league games since joining.
"Muriel has the kind of pace that is difficult to deal with, so we need to be even better at working together to cut him off," Spalletti added.
"We are in the right condition to play Fiorentina on level terms even in their own stadium and go there without fear.