Montella is without five players through injury, as Italian forward Giuseppe Rossi, whose strike rounded off a 3-0 hammering of Pacos Ferreira in their opening game in the competition, has joined midfielder Alberto Aquilani and strikers Ante
Rebic, Mario Gomez and Oleksandr Iakovenko on the sidelines.
Rossi, who is Serie A's top scorer alongside Torino's Alessio Cerci with five goals, suffered a calf injury in Monday's 2-2 draw against Parma.
Despite Fiorentina's injury woes, Dnipro coach Juande Ramos believes the Italians, who are fifth in Serie A, are still the team to beat in the pool.
"I expect a tough match with Fiorentina and I think it will be a nice game for the fans," he said.
"Although this is a balanced group, I think Fiorentina is favourite to clinch top spot.
"With Pacos Ferreira, we will fight for second place.
"Our aim is to win games and get as far as possible in this competition."
Ryder Matos will lead Fiorentina's attack at the Dnipro stadium with the Brazilian being the only striker available for selection.
Montella, meanwhile, has warned his players to be on their guard, with Dnipro unbeaten in eight European home games.
The Ukrainians started the competition with a 1-0 triumph over Pandurii in Romania.
"Dnipro is an experienced side," Montella said. "They have many Ukrainian internationals and play very well at home.
"We cannot underestimate them."
The Ukrainian outfit head into the contest on the back of last weekend's 2-0 triumph over Chornomorets.
The result kept them second in the Premier League standings, three points behind leaders FC Metalist Kharkiv.
The last time both teams met in continental competition was in the 2001-02 campaign, with Fiorentina beating Dnipro 2-1 in Florence after a goalless result in Ukraine in the UEFA Cup.