Must return to Atletico Madrid: Diego Costa

The 28-year-old Spain international had fallen out of favour with Chelsea's Italian coach, Antonio Conte, who reportedly asked him at the end of last season via a text message to search for another club, reports Efe.

"My destination is already made," Costa said in a statement. "I must return to Atletico Madrid."

"It turns out that there is the impasse that Chelsea does not want to release me," Costa added. "But I believe that this situation will be resolved now on my return to Spain."

The Brazilian-born forward has been in Brazil since last season ended, but the English Premier League's defending champions have expressed their wish to have him join their current training sessions.

Costa's attorney, Ricardo Cardoso, confirmed last week his client's intention to present a transfer request to the Blues.

Cardoso did not rule out taking legal action against Chelsea to ensure his departure from Stamford Bridge.

Chelsea, who paid 32 million pounds ($41.2 million) to sign Costa in 2014 from Atletico, seeks a 50-million pound (around $64 million) bid to let him leave, which is 26 million pounds ($33 million) more than what the La Liga side is offering.

If a deal were to be finally reached, Costa would not be able to play with Atletico during the first half of the season due to FIFA's ban that prevents the Spanish club from registering new players until January 2018, so he would presumably be transferred on loan to another club in the interim.