The move was negotiated by the agent of Martinez, Jorge Mendes, who also looks after Costa and attempted to get another of his clients, Radamel Falcao, a transfer deadline day switch to Atletico.
Telegraph Sport can reveal Falcao’s proposed shock return to Atletico until the end of the season collapsed because the Colombian could not pass a medical.
Falcao is out with a thigh injury and his only hope of cutting short his ill-fated Chelsea loan before the end of the campaign is now to follow Martinez to China before the Chinese Super League transfer window shuts on February 26.
Atletico only saw Falcao as a stop-gap option until the end of the season and will now attempt to start the process of taking Costa back to Spain, with the 27-year-old thought to be keen on the proposal.
Costa has returned to his best goalscoring form under Chelsea’s interim manager Guus Hiddink, but the Spain international is still believed to be unsettled with life in London and England.
Chelsea would insist on making a profit on the £32m they spent to take Costa from Atletico in the summer of 2014 to even consider allowing him to leave this year.
But, with Champions League qualification looking increasingly unlikely for Chelsea, Atletico will fancy their chances of tempting Costa back if they can get over the hurdle of their proposed transfer embargo.
Along with Real Madrid, Atletico were hit with a two-window transfer ban by Fifa over ‘irregularities in the signing of minors’. Atletico have lodged an appeal against the embargo in the hope of either overturning or delaying it.
- Telegraph