Chelsea boss Jose Mourinho has made it clear his senior players are crucial for the coming season.
Mourinho added 40 year-old former Fulham goalkeeper Mark Schwarzer this week.
"We are a very young squad. We have an average age of 26.3 and that includes Schwarzer who is 40 years old and JT, Cech and Lampard in their 30s, so if we don't involve these players we drop to almost an Under-21 team," said Mourinho.
"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."