Real Madrid and Barcelona are monitoring William Carvalho's situation at Sporting Lisbon.
Both Spanish giants have concerns about their midfield options and have been tracking Carvalho's stunning progress this season.
The 21 year-old is expected to make Portugal's World Cup squad and is fast emerging as being among the best young midfield talents in the game.
Carvalho penned new terms with Sporting last year, which included a buyout clause of €45 million.
