Ole Gunnar Solskjaer says Amad Diallo has made a "quite remarkable" impact in training and could be given his Manchester United debut soon.
The 18-year-old completed his move to United from Atalanta, which was originally agreed in October, this month.
Diallo did not start a competitive game for Atalanta, only making a handful of substitute appearances.
But Solskjaer has been impressed by how the winger has adapted so far and suggested he could be on the pitch for the first team within a month.
Solskjaer has previously praised Diallo's training performances and went even further ahead of Wednesday's game with Fulham.
"Very good [first impression]," Solskjaer said about Diallo.
"He can handle the ball, he has enjoyed training, makes a difference in training, which is quite remarkable at his age.
"Some adjustment to settle into the hustle and bustle of the Premier League but I can't see it's too long until he’s in the squad."
Asked if it might be four or five weeks until his debut, Solskjaer added: "It might be quicker than that, he has definitely settled down well.
"Players have taken to him, he is a good character, polite, smiley boy who works really hard.
"He is doing his sessions, getting used to us, there is always a period of adjustment needed but he is settling in well."
United boss Solskjaer expects one or two more players to depart before the January transfer window concludes.
He said: "I don't want to go into individuals but we can probably allow one or two more to go out.
"But the strength we have is we have a deep squad, strength in depth, we don't want to give our advantage away by easing off on our players, I can't give you a better answer than that."
Defenders Brandon Williams and Phil Jones were the only players who did not train ahead of the Fulham clash.
Solskjaer added United were still waiting for their latest batch of coronavirus results 30 hours after undergoing tests and hoped to receive them soon.