The Germany international has been sidelined since September with a knee injury, and was left on the bench during his side's Coppa Italia semi-final win over Udinese.
Gomez, who left Bundesliga giants Bayern Munich in the off-season, could still play a major role as Fiorentina look to seal a place in Europe this campaign.
He appears set to play some part against Inter at the Stadio Artemio Franchi, according to coach Vincenzo Montella.
"Mario is training well. He's enthusiastic about playing, but he's still not physically in top condition," Montella told a news conference on Friday.
"Hopefully he'll be able to play a little part tomorrow, but we'll have to wait and see.
"This game's a game in and of itself. It's a whole different story to the match last year."
Fiorentina's 2-0 win over Udinese on Tuesday saw them book a place in the Coppa Italia final against Napoli.
Montella said his side were feeling the effects of the victory, but warned his players they needed to stay grounded.
"The team is a bit tired, but it will be essential to restore our physical and mental well-being," he said.
"It's going to be a difficult game though because Inter have some great players who can really damage us.
"Hernanes has come in and has improved them already. He's a strong player and brings an element of unpredictability.
"Of course, we're on a high after the cup win, but we can't be too euphoric. We want to play with confidence, but we can't be overconfident."
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