The new Premier League champions now face the difficult task of keeping their talented squad together as cashed up clubs in England and Europe get set to circle this summer.
"We have won the title and we can do something good in the future," said Ranieri.
"I will tell them, 'If you go away, you don't know what might happen. Maybe you go to a big team and you won't be in the starting XI, then you will slow down. Here you are the king. Stay here one year more, then maybe you can go somewhere else'.
"That's why it's important to be careful in what you choose to do."