Tottenham Hotspur face a daunting task as they look to overturn a three-goal deficit against Atletico Madrid in the Champions League on Wednesday. Interim head coach Igor Tudor has revealed that January signing Conor Gallagher is a major doubt for the clash due to respiratory issues and a viral infection, though the coach is happy to have Cristian Romero back in the team.Spurs are sweating on the fitness of Gallagher ahead of their crucial round-of-16 second leg at the Tottenham Hotspur Stadium. The England international, who joined from Atletico Madrid in a £35 million deal in January, missed training on Tuesday and was absent from the squad during the weekend draw against Liverpool.Interim boss Tudor explained the situation surrounding the midfielder ahead of the conclusion of a tie in which they trail 5-2 on aggregate, stating: "We see today what we can do because he has, as you know, probably asthma problems. He has some virus to make some not nice things so we are going to see tomorrow if he is able to go on the bench. Nothing like a danger but still he is not able to play."While Gallagher remains a doubt, Tudor was able to deliver more positive news regarding other first-team regulars. Most notably, Swedish teenager Lucas Bergvall has made a surprise return to full training two months ahead of his original schedule. The youngster is set to be named on the bench alongside Destiny Udogie, who has recovered from a hamstring strain.Club captain Romero is also available for selection after completing concussion protocols following a head collision in the first leg. Tudor confirmed the defender's return, saying: "Romero, he's there. You saw him in training today? He can play. Joao [Palhinha], no, he's a little bit worse, so he'll be (available) for the next game. Romero is in."Away from the injury news, Micky van de Ven used the pre-match press conference to dismiss suggestions that the Spurs dressing room has become unsettled. The Dutch defender was vocal in his defence of the squad's commitment despite recent poor domestic form and the uphill struggle they face on Wednesday night.The defender addressed reports of players "switching off," saying: "Of course I've seen things. Reporters just say things sometimes and it's like: 'How did you come up with this?' Like players have switched off. It's not true."Add GOAL.com as a preferred source on Google to see more of our reportingThe London side host Diego Simeone’s men needing a minor miracle to progress in Europe’s elite competition. After a bruising first leg in Spain, Spurs find themselves trailing 5-2 on aggregate and must find a way to break down one of the most disciplined defensive units in world football without several key players. So far under Tudor, they have lost four matches and drawn one, having picked up a point against Liverpool on Sunday.