The Brazilian defender has been having treatment on his right knee because of a build-up of fluid within it, and missed Chelsea's training session on Monday to work with club physios indoors.
Conte told reporters: "David is out. This problem with his knee, trying to solve this situation. He's out."
When then asked whether Luiz's lack of involvement with the Chelsea first team pointed to a breakdown in relationship between the defender and Conte, the Italian replied: "Why do you ask this question?
"Two weeks ago, then it was the past, then he played against Qarabag. If you don't trust what I tell it's your problem not my problem."
"We try to see the young players in training sometimes."