Eden Hazard was excused from Chelsea’s Europa League trip to PAOK after twice telling Maurizio Sarri he was tired.
The 27-year-old playmaker led Belgium to third place at the World Cup and has been in scintillating form for the Blues.
Hazard scored a hat-trick last Saturday against Cardiff as Chelsea claimed a fifth Premier League win from five games before asking to be omitted from the trip to Greece.
Hazard received special dispensation to delay his return from his post-World Cup break until after the Community Shield on August 5.
He made substitute appearances in the first two Premier League games and has scored five goals in his subsequent three starts, delighting the Blues faithful who feared he would make a summer switch to Real Madrid which never materialised.
Brazil defender David Luiz has also been rested, having returned to become an integral member of the squad under Sarri. Luiz fell out of favour under Sarri’s predecessor, Antonio Conte.
Luiz’s compatriot Willian cut a frustrated figure under Conte, who was sacked after a fifth-placed league finish saw the Blues drop into the Europa League.
Willian was linked with summer moves to Manchester United and Barcelona and previously said he would have left Stamford Bridge had Conte stayed.
“I don’t want to talk about the past,” Willian said.
“I am very proud to stay and be a Chelsea player. It’s an honour to play for this club. I am very happy at Chelsea.
“Everyone knows what happened in the last window, but my mind was always at Chelsea.”
Mateo Kovacic has a minor injury and Emerson Palmieri is also not among the 21-strong travelling group.
Chelsea play at West Ham in the Premier League on Sunday and Liverpool in the Carabao Cup next Wednesday.
The 59-year-old former Napoli boss said: “In order to win our group, the match of tomorrow is the most important because it’s the most difficult match.
“In the first part of the season it’s very important to play with the same players.
“Tomorrow I have to change four, five players, but it’s impossible in this moment of a season to change 11 players for a match.”
That will not reassure Ruben Loftus-Cheek and Gary Cahill, who are yet to start for the Blues this season.
Willian wants to win the trophy again.
He said: “The way we play we can try to win titles. We want to start well and win this competition as well, so we go for it.”