Amartey became Leicester’s second addition of the January transfer window earlier this week, when he signed from FC Copenhagen.
The 21-year-old followed Demerai Gray to Leicester, and Ranieri believes that Amartey’s addition gives him further strength in depth both in defence and midfield.
“It’s good to have one player that can permit me to change something during the match,” Ranieri said. "He’s a good player, strong, with good quality, a hard worker and he has our spirit.
“He is a strong man and he can play in a lot of positions. He can play centre-back, right-back, central midfield and right midfield.
“It’s important for me to have another very good young player.”
Amartey may still have room to develop, but he has a considerable amount of experience of playing first-team football, having impressed while with Copenhagen.
The youngster will have a tough task breaking into Leicester’s team in the near future, however, as they have been flying this season.
Leicester have lost just twice this campaign, and Ranieri is unlikely to want to disrupt his squad by bringing too many new faces into his starting line-up over the next few months.