David de Gea-Sergio Romero
Sergio Romero replaced injured David de Gea in the Manchester United's last two fixturesGetty

Manchester United manager Louis van Gaal claims he is unsure when David de Gea will make a return from injury and says the goalkeeper could be doubtful for the second leg of the Europa League fixture against FC Midtjylland on 25 February. The Spain international was injured during a warm-up session before the first leg tie against the Danish champions.

The Red Devils suffered a 2-1 defeat in Denmark and they need to overcome the deficit at Old Trafford if they have to progress to the next round of the competition. After the last European fixture, the Dutchman confirmed De Gea will undergo scans to find out the extent of his injury.

IBTimes UK reported the scan on 19 February showed the knee injury sustained by De Gea is not serious. United progressed to the quarter-final of the FA Cup after defeating Shrewsbury Town 3-0 at New Meadow and Van Gaal confirmed the former Atletico Madrid stopper's injury is not serious as feared earlier.

"I don't know [if De Gea will be fit for Thursday], it is not so heavy but we have to wait and see when we can start him again," Van Gaal said, as quoted by United's official website.

After the Europa League clash, the 20-time English champions host Arsenal in the Premier League tie on 28 February. The Metro reports De Gea is expected to be fit for the clash against the Gunners.

In the FA Cup clash on 22 February, the former Barcelona and Bayern Munich manager welcomed both his full-backs, Guillermo Varela and Cameron Borthwick-Jackson. The latter was withdrawn after the break by replaced by Joe Riley, who made his United debut.

Will Keane also came in as a substitute in the second half and the striker, along with Borthwick-Jackson are the latest players to be added to the Red Devils' treatment room. Apart from the duo and De Gea, United's current injury list includes the likes of captain Wayne Rooney, Bastian Schweinsteiger, Matteo Darmian, Marouane Fellaini, Adnan Januzaj, Phil Jones, Marcos Rojo, Luke Shaw and Antonio Valencia.