The 22-year-old centre-back has been linked with a transfer to AC Milan but the Gigliati patron does not want to lose one of his key players during this transfer window.
“I have never talked to him about the possibility of a sale,” Commisso told La Gazzetta dello Sport.
“I want to keep him. He is a good guy and an excellent defender.”
Fiorentina have already acquired Giacomo Bonaventura and Borja Valero during the summer transfer window and Sofyan Amrabat has joined from Hellas Verona after being purchased earlier in 2020 but the Viola patron has not ruled out making more signings.
“If there are opportunities, we will exploit them, but don’t forget that there will also be the winter transfer market,” Commisso said.
“My advisors told me that it will be very lively.”