The veteran signed a two-year contract today, after 12 seasons at Bayern Munich.
“He is an extraordinary player, he's eager and we believe he can express himself at his levels here," Montella told Sky Sport Italia after dinner with Ribery and the club directors.
“He had his first training session today, but I was the only other one there, so I put my boots on after many years and had a kick-about."
On Ribery making his debut against Napoli, Montella added: “We'll see over the next few days how he responds to training and he is very determined, but we should take it easy. He was a little rusty, as was I."