Anthony Martial
Anthony Martial has been one of the few bright spots for Manchester United this seasonReuters

Anthony Martial missed out on Manchester United's game against FC Midtjylland, Thursday at Old Trafford. While warming up for the Europa League second leg, the French star pulled up and immediately, forcing Louis van Gaal to leave the striker out.

A last minute change in the playing XI was made and 18-year-old Marcus Rashford  was handed a debut for the club. The debut could not have been better, as Rashford ended with two goals to his name in Manchester United's 5-1 win.

The Red Devils already have a long list of injured players and they cannot afford to lose anymore ahead of the crucial period of the season. 

Martial's injury was a worry Van Gaal could have done without as the club face Arsenal this Sunday. With captain Wayne Rooney already out injured, Van Gaal is short on options up front.

Van Gaal, though, believes Martial's injury is not too serious. "It should be his first muscle injury. But he is smart and wise to step out. It is not a rupture or anything like that. A tight hamstring. I don't think it is very heavy," Van Gaal was quoted as saying by ManUtd.com. 

"Anthony can be tired. He's only 20 and he's played all the matches so it's not so remarkable. He stepped down himself and that I like very much."

Marouane Fellaini, Bastian Schweinsteiger, David De Gea, Adnan Januzaj, Antonio Valencia, Luke Shaw, Matteo Darmian, Ashley Young, Will Keane and Phil Jones are the other players who are sidlined because of injuries.

Marcus Rojo made a welcome return to the squad recently. 

"I have already explained to you the only muscle injury we have is Marouane Fellaini. That we know already when he played so many matches in a row. It's always like that when you don't have other players and it's difficult to change or rotate," Van Gaal added. 

"So the next muscle injury would be [expected to be] for Martial, but I don't think he has a muscle injury. He is very intelligent - he steps down when his hamstring is tight.

"You have to cope with that, it's difficult also for the team because, after David De Gea, now Martial, and Martial and De Gea have played very good seasons, I think, and they have to be replaced."