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. 
Just an estimate but I think hopefully it won't be that long. Hojlund has been key for Manchester United this season, he has found his game up front. Therefore, it would be a shame if he was absent for too long, Erik Ten Hag has also put his trust in him. Maybe the only option is to keep Rashford as a striker again, but we know that his level of consistency in scoring goals is very low. 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.