The Premier League side, who eventually finished fifth in the English top-flight standings last term and are expected to appoint ex-Chelsea boss Jose Mourinho as their new manager shortly after sacking Louis van Gaal after their FA Cup final triumph, are ready to make a move for the highly-rated Sporting Lisbon winger.
The 24-year-old, who has 31 international caps for his country, scored one goal and provided three assists in just seven appearances in all competitions for the Liga NOS outfit this season.
However Carrillo, has already agreed to join Portuguese rivals Benfica this summer on a free transfer, although the report suggests that the Red Devils could stunningly still bid for the right-sided winger before he has even launched his new career at the Estadio da Luz.
It is thought that Benfica could be willing to offload Carrillo to the Old Trafford outfit if they manage to make a healthy profit from this bizarre scenario.
And according to the reports, it seems a bid in the region of £19m could just do that.