The 18-year-old is widely regarded as one of the best up and coming left-backs in Europe and has already attracted scouts from elite clubs across the continent.
Liverpool reportedly made an offer of £19million for the left-back in the winter window, which was rejected by Sporting, who would have accepted £40m.
Man United and Liverpool could face competition in race to sign Sporting starlet Nuno Mendes
Manchester United are also keen on the teenager despite only signing Alex Telles last summer, while Real Madrid and Manchester City are also keeping tabs.
Now, according to Portuguese news outlet A Bola, Italian giants Juventus and AC Milan are keen to land in the summer and will battle it out with the likes of Liverpool and United should it come to that.
However, the report goes on to claim that any club willing to sign him will have to pay his whopping £63million buy-out clause this summer.
Reports claim that any club wanting to sign Mendes will need to pay his £63m buy-out clause
Mendes has played 24 times for Sporting since making his first-team debut back in June, scoring once and getting two assists, while he has become their first-choice left-back this season.
It is thought Mendes, who is a Portugal Under 21s international, could convert to a central defender in the future.