Real Madrid would reportedly be willing to sell Gareth Bale to Manchester United this summer if they were to get Romelu Lukaku in return.
Bale has been a long-term target for United and held talks with new Madrid boss Julen Lopetegui earlier this week as he seeks assurances over his future at the club.
The Wales international has hinted that he would be willing to leave the Bernabeu if he was not guaranteed more regular first-team football, with United the frontrunners to sign him should he decide that his future lies elsewhere.
However, Spanish outlet Don Balon claims that Madrid would demand Lukaku in return, having been impressed with the Belgian's performances at this summer's World Cup.
Madrid are ready to end their long-standing interest in goalkeeper David de Gea as they close in on Chelsea's Thibaut Courtois, but have now turned their attention to another of United's star players.
Jose Mourinho is unlikely to sanction the sale of Lukaku, though, even if it means once again missing out on Bale.
