And Hazard is the headline absentee from the 21-man travelling party for Thursday's match against the Greek side.
David Luiz, Mateo Kovacic and Emerson Palmieri have also been left behind by Sarri.
Chelsea have won all five of their Premier League matches under the Italian ahead of their clash with PAOK.
However, they had to come from behind to down Cardiff 4-1 at the weekend, with Hazard's hat-trick turning the game around after Sol Bamba opened the scoring for the visitors.
After the game, Sarri agreed with assertions that Hazard might now be the best player in Europe.
"I thought Hazard was one of the best players in Europe, but now I am changing my mind that he is the best," he told reporters.
"I think Hazard can improve more. I think that he can spend less energy than now at 50 or 60 metres to the opposite goal.
“When we have the ball in our half he touches the ball five times or six times. So his actions, it shows he spends a lot of energies, and can have more energy in the last 25 metres. I think he can score 30 or 35 goals.
“I have spoken to him in the last two days, yesterday I told him for me he can score 40 goals. But spend less energy far from the goal and play in the last 25 metres.”