Christian Eriksen will be out for three months with the ankle injury sustained against Reading on Saturday.
Manchester United will be without the midfielder, who was hurt in a shocking challenge by Reading striker Andy Carroll, until late April or early May.
Manager Erik ten Hag admitted United have no like-for-like replacement for the Danish playmaker but insisted his side can deal with his absence and backed Fred to step up as they have to play the majority of the rest of the campaign without Eriksen.
He said: “Of course he is disappointed, we are disappointed but it happens in top football. We have to deal with it.
“You can never fill that gap because every player has his own characteristics and identity. A lot of players will fill it in in a different way. It doesn’t mean you are less successful. It is quite clear Christian Eriksen brings top quality and has some specifics that are hard to replace [like] his quality in the final third and final ball.”
Fred scored as a substitute against Reading on Saturday and will get the chance to partner Casemiro in midfield for club as well as country.
Ten Hag added: “He is playing together with Casemiro in the Brazilian squad and that is not the worst squad in the world. They have so many choices they can make but they often prefer to play them together.
“That says something about the quality Fred has. When you see his performance for example against Tottenham or Manchester City, he has a lot of qualities. They are a really good combination, Casemiro and Fred.”
Eriksen will miss the Carabao Cup final, if United reach it, and their Europa League tie against Barcelona, though the Premier League club are hopeful he could be back before the end of the season.
The former Tottenham and Inter Milan player has made 33 appearances since joining United on a free transfer from Brentford last summer, scoring two goals. His total of seven Premier League assists is bettered only by Kevin de Bruyne.
