Costa's Chelsea future in limbo as he misses pre-season training
Chelsea striker Diego Costa will miss the start of pre-season training, Press Association Sport understands.
The 28-year-old's absence has been mutually agreed and he did not join the squad as they returned to work on Monday.
It is unclear exactly when the Spain international will return to training with the Premier League champions, who are due to travel to China and Singapore next week for their summer tour.
Costa claimed last month that Chelsea boss Antonio Conte had informed him in a text message he was not part of the Italian's plans going forward at Stamford Bridge.
He has been linked with a return to Atletico Madrid, who he left for Chelsea in 2014, despite the Spanish club's transfer embargo.
Last month, Atletico lost an appeal against a Fifa-imposed sanction which means that, while they can still buy players this summer, they will not be able to register or play them until January.
Costa scored 20 goals in 35 games as Chelsea regained the EPL title last season, but speculation about his future was rife.
He has previously ruled out any chance of moving to China as he does not want to jeopardise his World Cup hopes, but conceded trying to stay and fight for a starting place at Chelsea - with whom he has a contract until 2019 - is a waste of time.
Costa told the Spanish media after scoring in Spain's 2-1 World Cup qualifying win over Macedonia in June: "Things don't work like that. The fight for a place has to be fair.
"When there is a fair fight, you stay and fight but, if there isn't, then you have to go."
Costa's situation has been further complicated with Chelsea missing out on Romelu Lukaku, who is joining Manchester United from Everton.
The Belgium striker was reportedly Conte's top target and his arrival would have paved the way for Costa's Stamford Bridge exit.
Meanwhile, Chelsea's new signing Antonio Ruediger will also not be with the champions as they begin their pre-season.
The German defender signed a five-year deal with the Blues on Sunday, leaving Roma for a fee of £29 million (S$51.6m) that could rise to £33.3m.
Ruediger is set for some additional time off as a result of his involvement in Germany's recent Confederations Cup final win. - PA SPORT