Wolves have set the price for the midfielder at £20m.
The 23-year old enjoyed a terrific season for the Championship club, having scored 12 goals in 40 appearances.
And the club's managing director Laurie Dalrymple has stated that Costa would be available for the right price.
He said: "It will purely come down to whether someone comes in with an offer that's too good for us to turn down.
"We obviously feel that Costa is a very valuable asset.
"The only reason we wouldn't keep hold of that asset would be if it was in the club's interest from a financial point of view."