Vincenzo Montella's side have been without the striker since he suffered ligament damage to his right knee in a Serie A clash with Livorno in January.
Rossi's career has been hampered by knee problems, as he tore his right anterior cruciate ligament in 2011 during his time at Villarreal and only returned to action last May - almost four months after his move to Fiorentina.
The Italy international, who scored 14 Serie A goals in 18 appearances before his latest injury, has spent time in the United States as part of his rehabilitation process, and is hopeful of making a return in time for the final on May 2.
"I am working day after day to be there for the Coppa Italia final against Napoli," he said. "I don’t want to miss it.
"Our objective is to bring the Coppa Italia back to Florence for the joy of all our fans.
"Many champions have come through Florence and now I hope this team can give more joy to a city full of history."
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