It's been a long summer for Diego Costa but his transfer limbo looks set to end with an exit from Chelsea, according to Spanish outlet Marca.

What's the story?

Shortly after winning the Premier League with Chelsea last season, Blues boss Antonio Conte informed the Spanish striker he was surplus to requirements at Stamford Bridge and the signing of Alvaro Morata was the final nail in the coffin.

Named in the Blues' Champions League squad, having failed to secure an exit during the summer, it seemed Costa could have an opportunity at redemption in West London. However, it now seems any appearances will simply be a final swan-song for the controversial striker.

Marca state Atletico Madrid have reached an agreement with Chelsea to bring the striker back to Diego Simeone's side in the January transfer window, where the La Liga giants will see their transfer embargo come to an end.

The move comes as no surprise as The Sun reported earlier this week that Costa has sent his family back to the Spanish capital ahead of his return to La Liga, though it remains to be seen how much football he'll receive at Stamford Bridge in the meantime.

Risky move by Chelsea?

Chelsea have been heavily reliant on Diego Costa in recent years but seem uninterested in having two top-class strikers battling for a spot at Stamford Bridge, with Michy Batshuayi, a player yet to find his feet in the Premier League, playing understudy to the Blues' record-signing Morata.

A return to Madrid for Costa was always the likely outcome and it's a big step for Diego Simeone's side too, as they move to their new stadium, as it means they have a direct replacement for Antoine Griezmann should the Frenchman be lured elsewhere next summer.

Chelsea's biggest success though is getting £54m in the transfer market for a player they do not want, which is further evidence of the Blues' strong negotiations skills as they've previously got a lot of money for the likes of Oscar and Ramires to China.

Whilst the money from the Far East appears to be stagnating, prices in Europe have been on a meteoric rise in recent seasons and Chelsea have once again shown they have the ability to negotiate the best possible deal no matter who they're negotiating with.