The Brazilian striker was signed by Atletico from Portuguese side Braga in 2007 but has spent the intervening period on loan at Braga, Celta Vigo and Albacete before last summer joining Real Valladolid as part of the transfer that saw goalkeeper Sergio Asenjo move to Madrid.
Costa joined Valladolid on a permanent deal but there is a clause in his contract which will allow the Rojiblancos to re-sign the youngster this summer for one million euros.
Costa has not heard from the Europa League winners yet about a possible move back to the capital, but after an encouraging time at Valladolid, he feels he is ready to make his mark at the Vicente Calderon.
"I'm eager and hope to play at Atletico," said the 21-year-old, who scored eight league goals this season as Valladolid just failed to avoid relegation to the Segunda Division.
"I'm ready to do it. This season was very important for me because I had to show that I can play in the Primera Division and I think my performances have been good, but I know I must improve further still."