Michael Carrick has confirmed that Patrick Dorgu is facing a spell on the sidelines after suffering a hamstring injury against Arsenal last weekend, though the Man United interim head coach was unable to provide a clear timescale for the wing-back’s return, an update fans will not have wanted as they begin to find their form after Ruben Amorim's dismissal.Dorgu has been one of United’s standout performers in recent weeks, but his promising run was halted during Sunday’s 3-2 victory at the Emirates. The 21-year-old limped off late in the match, with initial hopes that the issue was cramp. Subsequent assessments have suggested the problem is more serious, with reports claiming the Denmark international could be sidelined for up to 10 weeks. In Carrick's system, the Denmark international has been given the freedom to charge up the pitch in more of an attacking role, and was crucial in the win over the Gunners, with his sensational strike from distance sparking the Red Devils' comeback.Speaking at his press conference on Friday, Carrick confirmed the injury would keep Dorgu out but stressed that the club are still evaluating the full extent of the damage."Pat, unfortunately, he's going to be out for a period of time. We're still working through how long that's going to be," Carrick said."We'll have to see, it's disappointing, he's had such a big couple of weeks, Pat. We weren't sure whether it was a little bit of cramp or whether it was something a little bit more serious and at the moment it looks a little bit more on the serious note."So, it'll be a few weeks for that. How many weeks? We'll have to wait and see. So, that's disappointing for all of us really, and for Pat, he's in such a good place, but unfortunately it is part of football and it's something we've got to work through and get him back as soon as we can."United are already preparing for life without Dorgu in the short term, with the wing-back set to miss Fulham’s visit to Old Trafford this weekend. Matthijs de Ligt will also be unavailable for that fixture, further limiting Carrick’s defensive options.There was more positive news on the fitness front, however, with Joshua Zirkzee returning to training and potentially in contention to feature for the first time under Carrick."Josh is back training this week, which is good news," Carrick added. "He's been out for a short amount of time, but first kind of training with us since we've been here, so that's great to have Josh back."United will continue to monitor Dorgu’s recovery in the coming weeks, with the club hopeful of reintegrating him as soon as medical staff allow.After hitting such a rich vein of form, United face a tough test in Marco Silva's Fulham this weekend, who currently sit seventh, and have picked up points against plenty of the Premier League's 'big 6' this term. Carrick has warned his players and the fans not to underestimate the Cottagers. He added: "I think the boys are in a good place going into the game. It's a tough game, tough challenge, I think Marco has got Fulham into a really good team."All of a sudden it is a different game, it's Fulham, just because we are at home, taking anything for granted is bang out of order."Add GOAL.com as a preferred source on Google to see more of our reportingFollowing Amorim's departure, the mood has shifted significantly at Old Trafford. There is now a genuine belief that the United can secure Champions League football next season, with the race currently wide open. The club have no other distractions for the remainder of the campaign, and Carrick has already hit the ground running. However, the former midfielder will be taking it one step at a time in a bid to restore their spot at the top table, where many fans feel they belong.