The midfielder was charged with drink driving earlier this week and was left out of Chelsea's squad for their trip to face Slavia Prague in the Europa League quarter-finals later on Thursday.
"(Drinkwater) has never played because... he's not suitable to my system, to my way of playing," Sarri told reporters.
"Maybe I'm wrong, but it's my opinion. I spoke with him in August, when the market was still open, and said he should look for something different because he wouldn't play. And I told him the reasons, my reasons.
"I don't know (why he decided to stay). Probably he hoped we could change the system. I have a very good relationship with him because, in my opinion, he's a good boy... but he's not suitable for me."
Sarri plans to make five or six changes for the Europa League match and says his side will need to be on their toes to get a result.
"In my opinion, this is a very dangerous match for us," he added. Slavia are a fast team, so we need to be very, very compact and defend really very well.
"They are dangerous, especially on crosses where they attack the box with five or six players, and are dangerous on counter-attacks. So it won't be easy for us."
(Reporting by Rohith Nair in Bengaluru; Editing by Simon Jennings)
