Courtois has regularly addressed his desire to return to Madrid, where he previously played for Atletico and where his two children live with his former partner.
Speaking on Sunday, Sarri said: "I have no reaction on the agent. I am not interested in the agent, I want to hear Courtois. If Courtois tomorrow (Monday) tells me the same, I have to speak with the club.
"I want only players with a high level of motivation. I don't have an answer for the agent."
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Courtois was due to return to training with the rest of Chelsea's players who made it to the closing stages of the World Cup.
The club put up a gallery of images from Cobham, which included shots of Courtois' international team-mate Eden Hazard, Ngolo Kante and Olivier Giroud.
Sky Sports News understand Chelsea have made Jack Butland their top target to replace Courtois if he leaves before Thursday's transfer deadline.
Source: Skysports
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