Drinkwater is yet to play under the former Napoli boss, who took charge of Chelsea for the 2018/2019 season.
The midfielder featured 22 times last season after joining from Leicester for a fee of £35million in September 2017.
Speaking to reporters on Wednesday ahead of their Europa League quarter-final at Slavia Prague, Sarri said: “He knows very well, he has never played because in my opinion he is not suited to my system and my way of playing.
“I told him everything in August, he appreciated but decided to remain and so he knew very well the situation.
“He’s not adaptable, that is my opinion. My opinion is important to me. Kante can play with two midfielders because he is a world champion. With the three he is better on the centre-right or left because I want a technical player.
“Jorginho against Brighton played 161 balls, for our way of football it’s important to have a centre midfielder that is technical and fast with the mind.
“Kante is wonderful for something different but not playing one touch.”