The Blues captain is expected to depart Stamford Bridge in the summer having revealed in January that his current deal would not be extended.
Lampard, who left the club 2014 after more than a decade of service in west London, feels the club is in danger of losing its identity.
"I do worry about where the real personalities of the team are," Lampard told the Daily Mail.
"To be a big team, you have to have big personalities. I don't want to sound like I am harking back to the days of me and John and Ashley Cole and Petr Cech and Didier Drogba but I do see a team now where John is the last mainstay of that identity.
READ MORE | 'Conte preparing for Chelsea job'
"We had a fantastic spirit at Chelsea. We are kind of famous for it now. People criticised us for it to try to take away the gloss of what we were doing. Maybe Chelsea are looking for a more beautiful way now.
"The club has been trying to push it down that route with the players they have recruited over the last four or five years.
"The problem is if you fall in the middle, somewhere between tough and beautiful. It's nice football at times but it's not that nice and it's not really winning games. It's not beautiful, beautiful stuff.
"They need to buy two or three big players. Because being 11th in the Premier League is ridiculous for Chelsea."