Speaking on talkSPORT, Gianfranco Zola said: "Some of Chelsea's current young players aren't ready, they need more time.
They used to have a core team of four or five players with the likes of Frank Lampard, John Terry, Didier Drogba among a couple of others.
"Chelsea would build their team around those players. Those players were the ones to spread those fundamental traits to the new players.
"Because the new players were in that environment with those core players, they could develop those attributes and abilities."
The balance at Chelsea has clearly shifted in recent years with a new transfer policy leading to a lack of leaders both on and off the pitch.
It remains to be seen whether the situation will change this as summer as Financial Fair Play rules restrict the Blues from making new signings.
