Atletico Madrid have not ruled out the possibility of resigning Diego Costa at some point in the future. Costa, 27, won the Spanish title with Atletico in the 2013-14 season before moving to Stamford Bridge for a reported £32m months later.
The Spain international enjoyed an outstanding first six months in English football and helped the Blues win last season's Premier League crown and the Capital One Cup, but has struggled to reach those heights this term in what has been a hugely frustrating campaign for him and the club.
Costa has himself admitted a return to the Vicente Calderon was something he could never completely rule out and speaking to RTVE, Atletico president Enrique Cerezo said: "Right now, Diego is a Chelsea player and he has to focus on Chelsea.
"But you never know what will happen in football and sometimes players do return to their former clubs."
Rumours linking Costa with a return to the Spanish capital have emerged in recent months and the striker made little effort to dismiss them following the Champions League win over Porto on 9 December. In an interview with Onda Cero he pointed out that Filipe Luis had already moved back to Atletico after just one season at Stamford Bridge.
"You never know - look where Filipe Luis is now. Life is full of surprises," he said. "I always wish Atletico the best and I always follow them, I support them from afar."
Costa however did dismiss claims he is unhappy in England. Speaking with IBTimes UK after the Porto match, Costa said: "It seems the English media want me to leave England as soon as possible. Because it's not normal what they say. But I do not speak English yet so the truth is that I do not hear what they say. When things are going well people put you in heaven and when things goes wrong they put you in hell. But the truth is that I'm happy here. Every day I am more settled."