Manager Antonio Conte says he has made his feelings clear to the Chelsea board about the urgent need to make new signings before the end of the transfer window.
The Blues have added quality with the summer signings of German defender Antonio Rudiger, Spain striker Alvaro Morata and French midfielder Timoue Bakayoko.
But with Diego Costa almost certain to leave and Nemanja Matic having been sold, Conte is worried by the champions’ lack of depth as they return to Champions League football.
Speaking at the Premier League launch event, the Italian said: “The signings were very good but we sold a lot in the summer – Matic and other players.
“Nathan Ake, Asmir Begovic, Nathaniel Chalobah and a lot of players on loan. For this reason it is very important to improve our squad and our quality.
“We have another competition but the club knows very well my opinion about this.”
Conte’s demeanour during pre-season has seemed increasingly unhappy. But he added: “For sure I am not frustrated because my role is the coach to train players and improve players.
“The club knows very well my opinion my and my idea and if we are able to do this I will be happy otherwise we will work in the same way.”