In a clear swipe at rivals Arsenal and Liverpool - both of whom have reached a Champions League final having finished fourth - Mourinho insisted change may be a good thing.
He said: "If the FA Cup winner becomes the fourth to qualify or if the FA Cup winner is one of the first three, I would be happy with that.
"The big teams here should not be afraid to finish fourth because maybe then they don't deserve to be in the Champions League."
Mourinho, whose side face Rosenborg in their opening group match tomorrow, added: "I will be on Chelsea's side, whatever that decision is.
"But Platini wants the influence of the Champions League in countries where it is difficult to reach."