In a recording, aired on Monday by French television station Canal Plus, shows Mourinho commenting on the Blues’ lack of depth up front and questioning the age of Cameroon forward Samuel Eto’o.
“The problem with Chelsea is I lack a striker,” he said. “I have Eto’o but he is 32 years old, maybe 35, who knows?”
Such comments have made many headlines and are understood to have irritated Mourinho, who did not know the light-hearted exchange was being filmed.
The remark about Eto’o is understood to be a reference to the supposed doubt about the true age of some African players.
Chelsea have not disputed the authenticity of Mourinho’s comments but are adamant that they were supposed to be light-hearted and not meant for broadcast or publication.