The Belgian youngster spent last season with the Toffees but has since returned to Chelsea.
However, the Blues are rumoured to see him as not yet ready for first-team action in west London, which has prompted talk he will be shifted on.
Everton have been linked with a move to bring him back either of a full basis or on loan for another campaign, but now Lukaku looks set for a switch to Spain.
Atletico recently sold Diego Costa to Chelsea and are known to have a good relationship with the Blues after taking goalkeeper Thibaut Courtois off of them for three seasons.
It now looks like that partnership will be used again, with the striker heading to the Vicente Calderon.
Lukaku himself is known to be looking to play Champions League football, which is a guarantee at Atleti after the club won La Liga last season.
He is also set to be a guaranteed starter, with Costa and David Villa having left the Rojiblancos.