Timothy Fosu-Mensah's new deal leaves Angel Gomes as the only remaining first-team player whose Manchester United contract will expire in June.
United do not have the option of extending the 19-year-old's current deal, meaning the club must tie him down to new terms before the end of June.
Whether the Red Devils can manage this remains to be seen, says the Mirror.
Gomes has featured sporadically for United in recent seasons, and is keen to play regular first team football.
He's also garnered interest from other sides including Paris Saint-Germain and Juventus.