Currently under a FIFA-imposed registration ban, Atleti failed to re-sign Costa, 28, in the summer, but Cerezo said the Madrid club will return for the Spain international in the new year, per Joe Short in the Express: "We cannot sign anyone until January, hopefully by then Costa and many others will come."
Short added Atletico tried to tempt Chelsea to sell striker Costa with a £25 million offer in the summer, but the Blues wanted £50 million for the player, who was told he was not in manager Antonio Conte's plans.
If the Spanish side had been successful in signing Costa before the start of the new season, they would not have been able to field him due to their ban, but the sanction will no longer be in place come the January transfer window.
Costa tried to force a move away from Stamford Bridge—where he moved to from Atleti in 2014—by effectively going on strike in his birth country of Brazil during the summer, but reports have suggested he may return to the Chelsea fold, per Matt Law in The Telegraph.
Dean Jones @DeanJonesBR
Besiktas are also in the mix for Diego Costa and would like him to join on loan. Understand club president currently in London.2017-9-7 16:03:38
Bryan Swanson @skysports_bryan
Fenerbahce say they've been in talks to sign Diego Costa on loan from Chelsea: "Move was close – the outcome is negative for now.” #SSN2017-9-7 20:58:23
In the long term, though, it is clear his preference is to return to Madrid, as he told the Daily Mail's Adam Crafton in August: "My desire is to go to Atletico. ... I have rejected other offers. They want to sell me to China or other teams. The language is better for me in Spain. If I'm off, I'm going to the club I want to go to, not the club that's paying the most."
It seems clear Atleti want him back and Chelsea want to get rid of him, so a move for Costa to Madrid in January looks inevitable assuming a fee can be decided.