Manchester United boss Ruben Amorim has issued fitness updates on midfield pair Bruno Fernandes and Kobbie Mainoo ahead of their Boxing Day welcome of Newcastle. United kick off festivities on Friday night as they look to bounce back from their 2-1 defeat at Aston Villa on Sunday afternoon and get their top-four push back on track having claimed one from point from their last two games.United came undone by a spectacular Morgan Rogers double at Villa Park last weekend, a result that leaves the Manchester giants three points off fourth-placed Chelsea. Amorim's side have a great chance to go level with the Blues this week ahead of the Blues' welcome of Aston Villa on Saturday evening.United's loss at Villa Park came at a greater cost after captain Fernandes was forced off at the break with a suspected hamstring problem, and the Portugal international is expected to be sidelined until the New Year. Fernandes' loss is a huge blow to Amorim, his compatriot having played a vital role in the middle of the park for United this season.And ahead of Friday's welcome of Newcastle, Amorim has issued a fitness update for both Fernandes and Kobbie Mainoo, who missed the Villa loss entirely due to injury.Speaking at his pre-Newcastle press conference, Amorim was asked whether Fernandes or Mainoo would be fit to feature in Friday's clash, to which he replied: "No, not for this game, they are recovering. I don’t think it will take a lot of time, I think Kobbie will return faster than Bruno. I don’t want to say. I have an idea, of course, but let’s see. We have other players, we need to maybe see different ways of playing."Additionally, Amorim also delivered updates on centre-backs Harry Maguire and Matthijs de Ligt, who miss out against Newcastle due to respective hamstring and back problems. "We are still working with them. They are not available for this one, but let’s see for the next one," the United boss said of the duo.Conversely, Amorim was full of praise for academy players Jack Fletcher and Shea Lacey, who both made their debuts off the bench against Villa last weekend. "I think Jack Fletcher did a very good job, and that’s why when we have these opportunities, we need to give space to guys like Jack and the other ones," the United boss said.And on the reaction to Fletcher and Lacey's respective debuts, Amorim added: "They are normal, they are good kids. The behaviour they have shown during this week are really good. I don't have the feeling that they were a little bit different because I played them for Manchester United."No, they are really focused, they are preparing for the game and they believe that they can play. That is a good feeling, so nothing different to what I saw in the last few weeks."Looking for smarter football bets? Get expert previews, data-driven predictions & winning insights with GOAL Tips on Telegram. Join our growing community now!The absence of Fernandes is significant for United, with the Portuguese midfielder targeting a return for the Manchester derby next month. However, Amorim believes it is 'impossible' to replace a player of Fernandes' calibre, stating on Wednesday: "It is impossible to replace Bruno but I say that this morning to the team, I think we need to take the good thing if there is a good thing on that, that a lot of people need to step up."It is not just the creation, it is every set piece, he is the guy who is organising the team and that is a good opportunity for everyone to step up and understand that we can't rely on one player for everything."Sometimes we rely on Bruno in the organisation, in the creation. We lost Bruno in set pieces we lost Bryan (Mbeumo) in those set pieces so this is massive for the team but it is an opportunity for players to step up and to show the leadership we need in the team."And on what the team loses without Fernandes, Amorim added: "Everything. Everything because he understands every position on the field. He pays attention to every detail. Every set piece when you have a substitution, he is always the guy who is telling the other guys where they should be."But that is a very good opportunity for guys like Licha, Luke Shaw, all these guys. We need to have more leaders to step up because this can happen to Bruno, it is not usual, but this can happen, so it is a big opportunity for the other guys."Add GOAL.com as a preferred source on Google to see more of our reportingUnited have a number of key players missing for Friday's welcome of Newcastle. Not only are Fernandes, Mainoo, Maguire and De Ligt all absent, but Mbeumo, Amad and Noussair Mazraoui are all on international duty with Cameroon, Ivory Coast and Morocco, respectively, at the Africa Cup of Nations.However, Casemiro returns for the game against the Magpies after he missed the Villa defeat due to suspension.