Italy forward Giuseppe Rossi
Rossi, who has scored 11 league goals for Fiorentina this season on his return from an injury nightmare, is still recovering from tonsillitis while tough-tackling AS Roma midfielder De Rossi has been struggling with a foot injury.
"Rossi definitely won't be there, even though he took part in the first training session today (Thursday)," Prandelli told a news conference. "De Rossi is available but will most likely start on the bench."
United States-born Rossi joined Fiorentina from Villarreal in January and has returned to action this season after successive knee injuries effectively cost him two years' of his career.
His absence means that Prandelli will have to wait before testing Rossi and Mario Balotelli in attack.
Prandelli also shrugged off worries about Balotelli's recent loss of form, which has also seen the maverick forward suspended twice.
"I've never seen him so well and so motivated," said Prandelli. "A great player knows that he is always under scrutiny and that each match hides pitfalls. He is a player who is feared all the world. "
Prandelli also announced that Southampton striker Pablo Osvaldo would take Rossi's place alongside Balotelli in attack, while Claudio Marchisio and Thiago Motta will join Andrea Pirlo and Riccardo Montolivo in midfield.
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