The former Barcelona captain is in his second season with the Serie A surprise packet.
Roberto recalled to Sport: "I took quite a gamble. It was a Serie B team that had just been promoted, I took a risk, but I saw it as a challenge.
"It's also true that from the moment I knew I was leaving Barça, I was talking to Cesc (Fabregas), and from the beginning, he gave me confidence. He explained the project very well, what it would be like in the future.
"I don't regret it. I took on a great challenge, and it's turned out incredibly well. Going from Serie B to fighting for European places speaks volumes about the project, the coach, and the club.
"It's a team with so many Spaniards, with Cesc, several Catalans, you feel a bit like you're at home. It hasn't been that different."