Former Napoli defender Ruud Krol feels they'll miss Kim Min-jae should the South Korea international leave this summer.
Kim's management team are said to be in talks with Manchester United.
Krol told Il Mattino: "He has improved a lot with the day after day work of a master like (Luciano) Spalletti.
"I must say the next a defender who comes to Naples won't be able to understand Italian football as quickly as the Korean."
Kim arrived last summer at Napoli from Fenerbahce.
