The 28-year-old Spanish striker, quarreling with the head coach of the "blue" Antonio Conte, continues the search for a new team.
Kostya's contract with Chelsea is valid until the summer of 2019, but right now the player's lawyers have begun work to break the current agreement.
Where Diego will continue his career - is still unknown. Among the possible options are present as the Spanish and English clubs, including Everton, whose coach has already announced his readiness to shelter a scandalous striker.
"I always said that we with open arms will accept any good player, and Costa is just that," said Ronald Cooman.
"We are still looking for an attacker. It's not that we are unhappy with Dominic Calvert-Lewin - on the contrary, I am very pleased with him. Nevertheless, he is only 20 years old, and he is our only option, while we need competition, "- said the Dutchman.
Last season, Costa scored 20 goals in 35 Premier League matches.
Earlier it was reported about the interest in Diego from the French Marseilles.