Maurizio Sarri intends to field Eden Hazard as Chelsea seek a fourth win from four Europa League Group L games at BATE Borisov on Thursday night, but in-form striker Alvaro Morata has been prescribed rest.
Hazard missed three games with a back injury, returning as a substitute in last Sunday's Premier League win over Crystal Palace, which featured two goals from Morata.
The Spain striker has five goals in his last six Blues appearances, missing a hat-trick chance against Palace, but Sarri opted to leave Morata at Chelsea's Surrey training base ahead of Sunday's league clash with Everton.
"He played three matches in a row, so I thought it was better for him to stay in Cobham to rest and to have two good training sessions," the Blues head coach said.
"It's normal for a player to play three or four matches and then rest. Otherwise, we can have a squad with 13 or 14 players."
The Italian reverted to his native tongue in an animated explanation, apparently riled by his decision being questioned.
David Luiz, Antonio Rudiger and Marcos Alonso were also left in London, while Cesc Fabregas was a late withdrawal with illness, necessitating a call-up for N'Golo Kante, who otherwise would have been rested too.
On Hazard travelling, Sarri added: "There is not any risk, otherwise he would stay in Cobham, of course.
"We thought for him it's better to play, not for 90 minutes, but to play after two weeks without training.
"In the last match he played only for 30 minutes. The best for him is he will play 45, 50 minutes."
Chelsea will be confirmed in first place with two rounds of matches to go if they win at BATE Borisov and the other Group L game, between Vidi and PAOK in Budapest, is drawn.
Mateo Kovacic warned against complacency, though, after watching Liverpool lose at Red Star Belgrade.
"I watched the game, Liverpool struggled a lot," the on-loan Real Madrid midfielder said.
"The most important thing is we need to be prepared so that what happened to Liverpool doesn't happen to us."