Ranieri handed Butelle his debut at Valencia, which ended with the keeper knocked out and facing the risk of his career being over.
He recalled to HLN: "It does something to you if the first person you see upon waking up after major surgery is your trainer, who is sitting right next to your bed.
"He was still there after another hour or two, remaining by my side. That shows his qualities as a man, for me no-one is better in that area.
"You should also know that the team left at that point for a training camp, to China ... But he has made time. For me, a young goalkeeper who actually had not really been part of the squad, that will stay with me forever."