Chiesa, 27, has been impressive in the first few weeks of the 2025-26 season, scoring two goals and providing two assists in his six games across all competitions.
Despite that, Slot decided to leave him out of the squad that will face Turkish side Galatasaray in the Champions League on Tuesday (September 30).
Slot has since explained the decision that left fans baffled, saying: "He got a little niggle, I think it is the word you use here in England, in the last game against Palace.
“He tried it today, he was on the pitch in the beginning but he couldn't end the session, so we decided not to take him because in a few days it's Chelsea again."
