The Serbian attacker is entering the final year of his contract at the Stadio Artemio Franchi, and AC Milan and Juventus are reportedly plotting moves.
However, Prade said that the club has planned talks with the 21-year-old, who is apparently keen to stay.
"We need to talk to the player, who has already explained to us his desire to remain in Florence," Football Italia quotes Prade as saying.
"Clearly conditions must be favourable for all concerned. There is time to discuss it and, if there are the right conditions, we'd be ready to renew his contract."
Ljajic scored 11 goals in 28 appearances in Serie A last season.