Manager Jose Mourinho has claimed Chelsea are not worried by their rivals' spending sprees.
Just like last summer, Manchester United have already added a large number of players to their squad and Manchester City have signed Liverpool winger Raheem Sterling for a fee that could reach £49m.
But the Portuguese says he is not surprised by all the signings being made by their rivals.
"I told the players that we are the same team and the others are not the same team," Mourinho is quoted as saying by Goal.com.
"I cannot stop opponents to make an assault to the banks and spend millions and millions. I cannot stop that. I cannot stop [that] the others have a feeling that we are playing against the champions.
"The others are spending.
"The others are buying a lot to try to be better than us and the fact that we are the same – we are changing a goalkeeper for another one, a striker for another one.
"It's a big challenge. To be better with the same people, the players have to be better individually than they were last year. So when they think: 'Oh last season I did great' this season it is not enough.'
"John Terry – great season. This season it is not enough. Must be better. Fabregas – I don't know how many assists last year. Fantastic. It's not enough.
"Because the others are going to improve with the players they are bringing and we have to improve by ourselves with our work."