Diego Costa appears unlikely to return to Atletico Madrid this summer despite the Spanish club being interested in re-signing the Chelsea striker.
The Spain international joined the Blues for £32m from Atletico in July 2014, but there have been widespread reports in recent weeks that he is unsettled at Stamford Bridge and would like to return to La Liga.
Atletico president Enrique Cerezo says he would like to bring Costa back to the club, but he accepts it will be "almost impossible" due to the difficulties of negotiating with Chelsea.
"He has a contract with Chelsea," Cerezo told Al Primer Toque Onda Cero.
"'There are many times when, as much as a I want a player, there is a contract.
"To negotiate with Chelsea can be really tough, almost impossible."
Costa, who is currently serving his second three-match suspension of the season, has scored 35 goals in 74 appearances for Chelsea.