Real Madrid would have to pay €75m to sign Porto defender Eder Militao.

The 20-year-old is being tracked by Manchester United and Real.

But any deal for the youngster has been complicated by a clause in his current contract.

According to Portuguese outlet O Jogo, Porto inserted a €75m in Militao's contract after signing him from Sao Paolo last summer.

United are working on a number of centre-back targets, with Napoli defender Kalidou Koulibaly at the top of the list.

Militao was previously viewed as a cheaper alternative before his release clause was reported.