Of course this is a bad blow for Man United, Casemiro's injury means that the list of injured Man United players has increased. Losing Casemiro is certainly detrimental to Man United because he is an important player in Man United's midfield, plus he is currently the top scorer so far with four goals in all competitions.
With so many players injured, Erik Ten Hag has to think smart about how to play players when facing Fulham next week. Because this match really determines the fate of Erik Tag Hag's future at Man United, Fulham is not a strong team. I think Erik tag hag should make the most of his opportunities.
Casemiro has missed matches several times, 3 in a row when he got red cards on two d occasion and Manx United did fine, they did well. If I remember correctly, that was when they were moving up and down between 3rd and 4th place and despite the speculations and oppression, they did fine in the outcome of those matches Casemiro was absent but his effort in their midfield is undeniable.
Fulham should not be a problem for Manchester United and I don't think that guy is getting sacked even if he lose that match. The worst case have not happened yet and I believe he is not going to stay back and watch Manchester United reach that level unless he doesn't want to remain in Manchester United. Fulham so far this season has done well playing against 3 teams that came from Championship to Premier League this season but the rest of the matches are not encouraging and I have assurance that Manchester United will used them uplift their place in the standing.
Every manager has a style and if they go to a new club, they still introduce that style of play in the new team. Pep went to Bayern Munich, despite the critics, he played the style of football he knows best, dominated and succeeded. Same thing with this Arsenal manager, Arteta, despite his early struggles, stuck with his beautiful possesion based football.
Forget about style of play in this situation. Sometimes, even the manager are helpless with the position of the club because you can't do much even with the best squad. That's life and we should understand that Managers are doing great work to display the progress of the team to the owners but it doesn't just work the way they want it to be. There is a loser and a winner and each managers come for the latter when they meet in battle but only one person will make it.