Manchester United reportedly sent a scout to watch Rafa Silva in action for Braga against Vitoria SC last night.
The winger has been linked with a host of clubs in recent months, including Barcelona, Atletico Madrid, West Ham United and Monaco.
However, the Red Devils have now entered the race to sign the Portugal international, according to A Bola.
The report adds that United are likely to speed up their pursuit if Jose Mourinho takes charge of the club in the summer.
It is believed that Silva has a £15.5m release clause in his contract, which is due to expire in 2019.