Manchester United are sweating on the fitness of Kobbie Mainoo and Luke Shaw, with both at risk of missing the trip to face Atletico Madrid.Michael Carrick and his players fly to the Spanish capital on Monday afternoon, but as is customary for United before Champions League games, they trained at their Carrington base in the morning.That session did not include Mainoo or Shaw, both of whom started in the weekend draw against Tottenham Hotspur.Club sources insisted that by mid-morning a decision was still to be made as to whether either player would travel to Spain, with £70m summer signing Carlos Baleba ready to step in for his first start should Mainoo not be fit to go.Mainoo pulled out of England duty over the recent international break to a combination of injury and workload management, and United are keen not to run their prized young midfielder into the ground too early.Matthijs de Ligt, who hasn’t featured for United since November 2025, trained but is not expected to feature away to Atletico. Harry Maguire and Youri Tielemans in training on Monday ahead of United’s trip to Madrid Carlos Baleba, a £70m summer signing from Brighton, may make his first startThe concern around Shaw is escalated by the fact that United are already without left back alternative Dorgu, who was injured playing for Denmark during the international break.Noussair Mazraoui, another left back alternative, is also sidelined and missed Monday’s training session, leaving Carrick and his staff with a dilemma if Shaw can’t travel.Shaw was officially granted a designated rest day ahead of the FK Sabah game, only to not be involved in the match as the club managed his minutes.That becomes infinitely harder with Diogo Dalot and Harry Amass, both of whom trained, now the only conceivable left backs available for the Madrid trip if Shaw fails a late fitness test.Leny Yoro’s emergence at right back, where he played relatively well against Tottenham, sets up the prospect of United playing Dalot at left back and Yoro at right back against Diego Simeone’s relentless Atletico attack.Atletico, meanwhile, insist they will not take United lightly despite their dismal start to the season.United’s record of one win from their first six league games is the club’s worst in 40 years, and they also crashed out of the Carabao Cup to Brighton.At least, they made a winning start in Europe with a 4-0 win at home to Sabah of Azerbaijan, but this is a much tougher test at the impressive 70,000-capacity venue that will host this season’s final.But head coach Simeone has warned his players not to pay too much attention to United’s poor form, saying: ‘In terms of the results in the early stage of the season, they are still Manchester United, a very strong side, and we need to play the game so we can punish them.‘Tomorrow we are up against a very good team in terms of playing in the opposition half. They are very aggressive and good at taking time away from you. We have to respect them.’ Kobbie Mainoo played 90 minutes against Tottenham after missing the international breakAtletico defender David Hancko echoed his manager’s comments as Atletico try to bounce back from an opening defeat to Liverpool at Anfield.‘United are in and out of the Champions League, but to finish third last year in the Premier League, which is one of best leagues in the world from mid-table to lower table, that says a lot about them. You know how much these kind of clubs can pay for players,’ said the Slovakia international.‘Maybe even now they are not coming from a great start of the season, but they have amazing players. We are not looking like we are giant favourites tomorrow. It’s going to be really difficult with their threat, and we need to play 110 per cent to get the result. To get them from the second pot is not an easy draw.’United beat Atletico 2-1 in a pre-season friendly in Stockholm, but neither Simeone or Hancko is putting much stock by that result. ‘We were missing seven or eight players and we are focussing on it more than we did during the pre-season,’ said Simeone.Hancko added: ‘We know that we lost the game but when you look at the players, I think in this sense it’s going to be quite different.‘But I think we are in a good form and what we learned from that game. The coach was emphasising their quality, their physicality and how fast they like to play, so it’s going to be crucial to be even better tomorrow. How have a lot of threat in attack, but I believe in their defence so we can manage it. We have strong attackers and I believe we can win.’On the prospect of Atletico playing in the final in their home stadium in June, Hancko said: ‘Last year we were really close to play in the final. It would be amazing to play here, but it’s really far away. Our job is really difficult and we need to look at it match by match. We need to win lots of points right now in the league phase.’