Diego Costa trained by himself for the second straight day on Monday as the rest of the Chelsea squad enjoyed time off.
The Blues squad were given two days off by boss Antonio Conte following their 3-0 win at Leicester on Saturday.
Costa did not travel with the squad to the King Power Stadium.
A back injury was the official reason for Costa's absence, but Sky sources understand a training-ground row with Conte happened against the backdrop of a £30m-a-year offer from Chinese club Tianjin Quanjian.
Sky sources also understand Costa will meet with Conte - who has also been off work since Saturday - on Tuesday to try to find a way forward.
Chelsea players will also return to training on Tuesday morning.
Costa’s injury will continue to be monitored by Chelsea’s medical team and a decision will be made on Tuesday to see if he can return to full training with the rest of the Chelsea squad.