Manchester United representatives were sent to Portugal to watch William Carvalho for the eighth time this season, reports the Daily Mail.
Reports surfaced yesterday that United were present at Sporting's game against Académica while O Jogo has confirmed it was the eighth time they have watched over Carvalho.
David Moyes is preparing for a busy summer transfer window as he continues to rebuild a faltering Manchester United squad.
Juan Mata was brought in from Chelsea in the January transfer window to provide creativity while Sporting Lisbon's Carvalho has been targeted to shore up the defensive side of the midfield.
The 21-year-old has been in inspiring form for the Portuguese outfit and has had scouts from Arsenal also check his progress this term.
Manchester United remain favourites to secure his signature, however, with their interest good enough to make front page news in Portugal.
The transfer of Carvalho will be far from easy for Moyes to negotiate. The youngster is part-owned by a third party and reportedly has a release clause of £37.5m.
The complicated nature of Carvalho's ownership would have made signing him in January a tough prospect but United will have more than enough time to negotiate a deal in the summer.