Lukaku has been one of the young stars of the Premier League in the past couple of seasons having had spells on loan at West Bromwich Albion and Everton - scoring 32 goals in 76 Premier League appearances.
The potential deal for Lukaku is of 'part of several operations' according to the report following a summer where Chelsea have picked up a few of Atleti's title winning stars.
Forward Diego Costa has completed his move to Stamford Bridge whilst Thibaut Courtois - who has spent several seasons on loan at the Vicente Calderon - is expected to be recalled to West London, with murmurs that long time number one Petr Cech is expected to be sold.
Tiago is expected to rejoin the club whilst Chelsea are said to be in talks over signing Atleti left-back Filipe Luis - who is said to have asked the Spanish Champions to lower his release clause so the Blues can agree a fee for the Brazilian.
Lukaku's relationship with Chelsea boss Jose Mourinho didn't seem at its best last season when the forward was on loan at Everton - with one notable occasion when Mourinho said Lukaku should reveal 'the real reason' he was sent on loan to Merseyside, as there were hints from the Belgian that he would like to have stayed at Goodison Park.
The Belgian is still only 21 and with the arrival of Costa at Stamford Bridge, Mourinho may feel it is better for Lukaku to be loaned out and get some experience of top level football in a different country to aid his development.
Lukaku is said to have been a transfer target of both Everton and Tottenham Hotspur so far this summer.