Ex-Chelsea defender Ron Harris believes supporters could get impatient with Frank Lampard.
The Derby County boss, 40, is expected to replace Maurizio Sarri at the Blues helm, despite only having one season of managerial experience.
"If you look at the top-class managers who have been there, they don't seem to last more than two years," Harris told Love Sport Radio.
"[But] if Frank did decide to come, I think things would change a little bit and they would give him some time, especially if the transfer embargo comes into force.
"The question is would [Chelsea supporters] be happy if it takes two or three years to bring these [young] fellas through?
"No disrespect to the players out on loan, there is a big, big difference between playing in the lower divisions and having to come and play in the Premiership.
"As much as some of the lads have done ever so well at Derby on loan, I think it is a different ball game.
"I'm not knocking sides in the lower divisions, but there are half a dozen tremendous sides in the Premiership. Sometimes supporters can get very impatient."