Sofyan Amrabat missed Morocco's Africa Cup of Nations qualifier against Liberia due to an unspecified injury, according to Moroccan media outlet Al Ayam.
The Man United midfielder was left out of the friendly against Ivory Coast on Saturday but could not recover in time for a more important game.
"We will not hide behind absences, because we knew about Amrabat’s absence before the start of the camp," Morocco head coach Walid Regragui said in between those games.
Amrabat has played five games for United since joining them on loan, mainly stepping in as a makeshift left-back.
His medical ahead of the transfer detected a back problem, but the Red Devils went ahead with the transfer anyway.
Man United have been hit with an injury crisis, with 16 players missing games this season.