The Italy international's first 12 months in England were plagued by injury.
Calafiori told La Gazzetta dello Sport: “Last year injuries stopped me because in the matches I was used in I think I always responded in the right way. That's why now I'm only focused on working well and finding the best condition. I'm ready.
"The intensity in England is completely different from that in Italy, but for me, it wasn't a problem at all. In fact, I feel like I've been here longer, forever."
In September there will be two World Cup qualifiers, with Rino Gattuso having replaced Luciano Spalletti as Italy coach.
Calafiori also said, "I spoke to Gattuso on the phone and he made a great impression on me. I'll meet him on the pitch at Coverciano
"Let's just say the situation we're in isn't easy, but we have to believe in it. Italy can't miss another World Cup."