The 30-year-old was injured in Saturday's World Cup qualifiers 3-2 defeat to Serbia, and the Romanian Football Federation confirmed his absence from Wednesday's game with Austria.
"This morning we found out that Adrian Mutu will not be able to play. After he returns to Florence, he will undergo surgery," the FRF said in a statement.
However, Fiorentina refused to acknowledge Romania's surgery suggestion, stressing that Mutu will undergo tests in Florence first.
"He will come back to Florence tomorrow. On his arrival he will undergo tests with the club’s medical staff and the condition of Adrian Mutu will then be announced officially," a club statement read.
"Up to that point any rumors about the type of injury are without foundation."
Mutu hit 13 Serie A goals with Viola so far this term, forming a lethal partnership with Alberto Gilardino.