The 22-year-old has been in sensational form for the Eagles this season, scoring 34 times and providing six assists in 40 appearances.
He still has more than three years remaining on his contract with the Portuguese giants but the club are unlikely to be able to keep hold of him during the upcoming transfer window.
Manchester United have allegedly earmarked Benfica teenager Joao Felix as their top summer transfer targets.
The 19-year-old forward has emerged as one of the hottest prospects in European football this term by playing a direct role in a combined 26 goals in the Primeira Liga and Europa League.
Tottenham Hotspur have reportedly expressed an interest in making an audacious move for in-demand Benfica youngster Gedson Fernandes.
The 20-year-old midfielder has already been linked with a move to Premier League giants with the likes of Manchester United and Liverpool.
Fernandes’s representatives are rumoured to have been in England last week with potential suitors.