3-5 weeks? 
It is a really long time period for the Red Devils. They are really unlucky about his injury. As far as I remember he was injured for a while when he first arrived here as well. The fans would hope to see him healthier than this. Especially while there is a big improvement in his performance the team need him a lot. 
I think he got a muscle injury recently because he was featured in the last Manchester United match against Luton and he was the one that scored their two winning goals(1 and 7 minutes of play). It is a really long time period for the Red Devils. They are really unlucky about his injury. As far as I remember he was injured for a while when he first arrived here as well. The fans would hope to see him healthier than this. Especially while there is a big improvement in his performance the team need him a lot. Hojlund is going to be missed in today's Manchester United match against Fulham but still, I believe that Manchester United could win against Fulham without Hojlund since the match is being played in Old Trafford. It is for Ten Hag to change the formation of playing Rashford as a center forward and introduce a new player to play side wing in replace of Rashford's position. That ends it.
What should be Manchester United's major concern is when they meet Manchester City in their upcoming match after their todays match against Fulham