Chelsea boss Jose Mourinho says letting Frank Lampard go last summer was the right decision for the club's future.
Lampard, 36, initially joined MLS side New York City on a two-year deal before signing for sister club Manchester City on loan until the end of December.
City are battling Chelsea for the Premier League title and want to extend the impressive midfielder's loan deal.
"The project is to prepare for the next 10 years, not the next year - we made the right decision," Mourinho said.
Lampard left the London club after 13 years at Stamford Bridge in which he became the club's record goalscorer with 211 goals in his 649 appearances.
Champions City are three points behind league leaders Chelsea with 36 points from 16 games.
Chelsea negated the loss of Lampard by signing Spain international Cesc Fabregas, while also bringing back former striker Didier Drogba, 36, and retaining 34-year-old centre-back John Terry.
"You can argue 'You have John Terry and Didier Drogba'. Different. Drogba is a striker that is coming to help and support the team," Mourinho said.
"John Terry is the best central defender in English football and it doesn't matter how old he is.
"The nucleus of the team has to be developed and to have a big player like Frank we would stop the development of the other guys."
|Leading scorers in the Premier League|
|Alan Shearer||260||441||Blackburn, Newcastle|
|Andy Cole||187||414||Newcastle, Manchester United, Blackburn, Fulham, Manchester City, Portsmouth|
|Wayne Rooney||178||385||Everton, Manchester United|
|Frank Lampard||175||588||West Ham, Chelsea, Manchester City|
|All stats correct as of 15/12/2014|