The Serie A outfit had earmarked the 23-year-old as a valuable addition to their back-line and were hopeful of luring him to Firenze in the January transfer window, despite competition from across Europe.
However, with Barcelona being unable to sign any new players due to their transfer ban, the Liga giants ultimately refused to sanction the player's exit.
"Montoya is a very interesting player, but Barcelona do not want to sell any players because of their transfer ban," Prade told Sky Sport.
"So negotiations for him never really took off."
Montoya came through the ranks of the Barcelona youth academy, but he has so far been unable to displace Dani Alves as the club's first-choice right-back.
The Spain international has a contract with the Catalans until June 2018.
