Chelsea boss Jose Mourinho has hopes for young duo Tomas Kalas and Kevin de Bruyne.
Mourinho believes the integration will only be positive.
The Portuguese boss said: "They are good players with a very good value in the market and we have these players this season for free, after an investment that the club did before.
"After the development of the players on loan it is the right moment for them to be back.
"They are very young with space to develop, they will be better year after year and I can imagine in five years they are much better than today - but what they have today is more than enough to belong to this squad.
"We have a team to develop, we have a team to work. Of course we know there are expectations already and we want to create expectations for ourselves, we don't need other people to create them.
"But the reality is the best period of this team has yet to arrive because they are very young and in five, six, seven years' time is when this team will be in the best moment of their careers."