All four players have been linked with moves away from Stamford Bridge, but when asked if he would phone the quartet to establish their plans, Sarri said he would rather wait to speak to them face to face, per David Woods in the Daily Star:
"I don't think so honestly, because clearly the players you are referring to are very high-level players. I would like to keep them in my squad, but a telephone call without looking them in the eye will not give me any certainty.
"I would like to meet these players face to face and talk to them and understand what the best thing to do for everyone."
Per Woods, Belgians Courtois and Hazard have both been linked with Real Madrid, Willian with Manchester United and Kante with Barcelona.
All four are crucial components of Chelsea's squad, and Sarri would likely be loath to lose any of them.
The 59-year-old Italian's long-awaited confirmation as Chelsea's new manager was announced last week.
He has a big job on his hands to reinvigorate the Blues after they could only finish fifth in the Premier League last season, 30 points back from champions Manchester City.
Willian got to the quarter-finals of the 2018 FIFA World Cup with Brazil, Courtois and Hazard were in the last four with Belgium and Kante was a key part of France's winning squad.
As a result, all four are still on holiday, and Sarri will have to wait to meet with them.
The summer transfer window closes on August 9 this year for Premier League clubs, so Chelsea will have to be organised about bringing in replacements if any of them leave the club.