The midfielder is a target for Inter Milan.
“Where will Roma restart from? A super season, which no-one predicted," the goalkeeper told reporters from Brazil's base in Russia.
“We overcame Chelsea, Atletico and Barca, and although it didn't go as we wanted against the Reds, we went out with our heads held high and certain mistakes won't be repeated.
“Juve? I'm only thinking about Roma, but in moderation. The word 'Scudetto' gets thrown around a lot, but we need balance and awareness.
“Nainggolan? He's very good: if we want to raise the bar, having a player like him is crucial. My future? I understand the fans want answers, but I'm focused on the World Cup.
“We'll make a decision after Russia."