Chelsea Transfer News: Diego Costa Eyed by Atletico Madrid, Fresh Blues Rumours

Chelsea striker Diego Costa could reportedly be on his way back to former club Atletico Madrid following his poor form in the 2015-16 campaign.  

He has netted just three times in the Premier League this season and looks a shadow of the player whose goals helped Chelsea to the title last term, per WhoScored.com.

Costa's relationship with manager Jose Mourinho seems to be deteriorating—he recently threw his training bib at the Portuguese after being benched—and Atleti are reportedly weighing up whether they should activate his £28 million release clause, per Spanish outlet Mundo Deportivo (via Metro's Sean Kearns).

The Blues signed Costa from the Madrid outfit on a five-year deal for £32 million in July 2014, and he went on to score 20 league goals in his debut season for Chelsea, per WhoScored.com.

This term, though, a combination of off-field issues and poor on-field performances have led to long-term speculation that he may be primed for the exit door at Stamford Bridge, per Bleacher Report's Dean Jones:

Costa would surely be open to a move back to the club where he thrived between 2010 and 2014.

However, the idea that he would be available for less than £30 million—and less than Chelsea paid for him—is dubious.

He still has more than three years remaining on his contract and, at 27 years old, should still be in the prime of his career for the next few seasons.

While 2015-16 has, thus far, been a poor one for Costa, he has not turned into a bad striker overnight, and if Chelsea are indeed looking to sell him, they will surely still want to make their money back at the very least.

CHRISTOF STACHE/Getty Images

Bayern Munich superstar Thomas Muller is reportedly being eyed as the man to replace Costa in west London, per Darren Lewis of the Daily Mirror.

The German forward will surely cost in excess of £50 million, and Chelsea will want Costa's sale to fund as much of the transfer fee as possible.

Letting him go for less than they paid for him would be foolish, and it would buck an historic trend of very effective transfer business done by Chelsea under Mourinho and owner Roman Abramovich.