Goalkeeper Thibaut Courtois believes Chelsea will have to spend big if they are to mount a strong challenge for the Premier League title next season.
The Belgium international expects the likes of Manchester City and Manchester United to splash the cash this summer, leaving the Blues to play catch-up after they finished down in fifth place in the table this season.
I think we'll see after the World Cup whether I am a Chelsea player for next year.Thibaut Courtois
When asked by Sky Sports if he felt a big summer spend was needed, he replied: "Yes, I think so. I think especially if you see how City and United are spending and working.
"I think if we want to aim for the top we should do the same - obviously within the limits of what's possible as well.
"I think that the transfer market has gone pretty crazy. Nowadays, you pay £80million for a defender I think - that's crazy figures.
"We'll see what's going on and I am sure the board will do what needs to be done."
Meanwhile, Courtois also said he would make a decision about his own future after playing at the World Cup finals with Belgium this summer, with the goalkeeper out of contract with the Blues at the end of next season.
He added: "We'll see what is going to happen after the World Cup.
"Like I have said in the last weeks and months, I think we'll see after the World Cup whether I am a Chelsea player for next year."
Courtois, who spent three seasons on loan at Atletico Madrid, has been heavily linked with a move to Real Madrid this summer.
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