Ribery is under consideration at Juve as a replacement for veteran midfielder Pavel Nedved and Toni told Tuttosport: "Nedved is a great champion, but, in my opinion, Ribery is stronger.
"Franck is playing outside left for Bayern in a 4-4-2 system, the position he wants. Within a few years, he'll become one of the top three players in the world. He's a real phenomenon.
"It's normal for the big European clubs to follow him carefully. But if I were the manager of Bayern, I would not ever let him leave."
Toni also revealed: "He asks me a lot of questions about Italian football. He's also learning the language, but only so we can speak with eachother."