Anderson has been in sensational form for Lazio since Christmas.
"He is 70% of his potential, when he has completed his physique, we'll see exactly how good he is," Zavaglia told Leggo. "Watching him play against those of the same age you could see he was clearly superior to all.
"I saw him by chance in a Paulista championship match with the shirt of Santos, that year they had a team of other future champions like Rafael (now with Napoli), Jonathan (Inter), Neymar (Barcelona), Ganso (Sao Paulo) and Danilo (Porto).
"I was impressed because he was several levels above the peers of his age."