It remains unclear where Lukaku fits into Jose Mourinho’s future plans at Chelsea, with the last two seasons spent out on loan at West Bromwich Albion and Everton.
Both stints have served to underline that the powerful Belgium international has what it takes to be a top Premier League striker.
He is, however, yet to make his mark at Stamford Bridge and has seen Chelsea close on a big-money move for Diego Costa – a man who would provide further competition for places in west London.
Should, as expected, Costa complete a switch to England, Lukaku could find himself heading in the opposite direction – with a loan move mooted as part of the agreement.
Robles feels the 21-year-old would be a big hit in Spanish football, having played alongside him during the 2013/14 campaign at Goodison Park.
He told AS: “He asked me about the Spanish league and what our league is like.
“He is very interested in other leagues, like the Italian one and ours.
“Lukaku is the sort of player Cholo (Atletico coach Diego Simeone) likes. His characteristics, desire, dedication and strength are exactly what Simeone wants.
“Apart from being physically strong he is also very technical because he is such a complete forward.
“If Atletico do end up signing him, he would be a great addition.
“He is a very physical player and very strong. He is very difficult to stop, an animal. He is intimidating, like a beast. He is a complete forward.
“The Premier League is not like the Spanish league. They are totally different. But I think with his characteristics, he would adapt to the Spanish game.
“He would fit in perfectly because he is a great player and there is always room for good players.”