The Stamford Bridge side missed out on the signing of Wayne Rooney and have high hopes for Romelu Lukaku, while the Cameroon striker will add competition for places
The Blues pursued Rooney during the summer transfer window before eventually admitting defeat in the chase for the Manchester United striker, signing the experienced Cameroon international instead.
Eto'o played under Stamford Bridge boss Jose Mourinho at Inter, and Emenalo is confident the former Anzhi man fits the club's short-term plans perfectly.
"In the case of Samuel Eto'o, it was an open secret that we wanted Wayne Rooney and I don't need to explain what the idea is behind wanting a player like Rooney," he told Chelsea's official website.
"But we are not desperate and we know for the future we have Romelu Lukaku and incredible hope that he will come through and lead the line.
"People keep forgetting that he is only 20, and looking at the short-term plan, we don't want to put too much pressure on a young player like him.
"So if we weren't able to get Rooney and we had Lukaku, Ba and Torres, we felt comfortable with them but we also felt comfortable to bring Eto'o to give us a little bit of competition, because we wanted to freshen up that position."
Eto'o, meanwhile, limped out of Cameroon's 1-0 victory in a World Cup qualifier over Libya after playing for an hour.