Costa's Chelsea future was uncertain after a blazing row with manager Antonio Conte.
The two have since made up – with the striker set to start against Hull today (430pm).
However, Costa is not short of admirers.
Express Sport understands there is a £30-million-a-year offer from the Chinese Super League on the table.
Diego Costa will cost clubs £130m if they wish to sign him
Diego Costa is expected to start against Hull today
Chelsea train ahead of Hull clash
Fri, January 20, 2017
Express Sport brings you all the best snaps as Chelsea train ahead of their clash with Hull on Sunday
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Diego Costa was all smiles as Chelsea train before their clash with Hull
And La Liga duo Barcelona and Atletico Madrid are also reportedly keen to snap him up.
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Barcelona are keen to sign Costa as a long-term replacement for Luis Suarez, who turns 30 on January 24.
But the forward will not come cheap.
Chelsea want Diego Costa as a long-term replacement for Luis Suarez
Chelsea believe they can get as much as £130m for Costa and are even open to selling the 28-year-old this month.
Costa has been wanted by clubs in China since last season and the player has had his head turned by the riches on offer.
Chelsea would likely aim to get as much money as possible for the striker, and Costa's unhappiness at Stamford Bridge could lead to a sensational transfer this month.