Danilo joined Porto from Maritime in July 2015 and has since established himself as a key member of Sergio Conceicao’s side.
The 26-year-old was linked with a move to Manchester City and Paris Saint-Germain during the summer but a deal never materialised.
And any side hoping to tempt Porto into selling would have to meet the £55million release clause included in Danilo’s contract, which he only signed in January.
He was a key member of the Portugal side which won the European Championship in 2016, although he didn’t feature in the final.
And his recent performances for his country have caught the eye of Barcelona chief Robert Fernandez.
That’s according to Spanish outlet Mundo Deportivo, who claim Fernandez has targeted Danilo as the ideal successor to Sergio Busquets once he decides to hang up his boots.
Barcelona don’t have a lot of depth in that area of the field with Andre Gomes often used as a back-up but he has been linked with a move away from the Nou Camp.
However, the report suggests Barcelona could face competition from City and PSG who could revive their interest in Danilo, while Arsenal have also been touted as potential suitors.
Fernandez also took the chance over the international break to keep an eye on the development of AC Milan forward Andre Silva and Sporting Lisbon winger Gelson Martins.