Manchester United have been handed yet another injury blow after Chris Smalling was reportedly ruled out until Christmas with a groin strain.

According to the Mirror, the United defender, who was substituted 18 minutes into the Old Trafford side's 2-1 victory over Southampton, has been ruled out for a fortnight and will surely miss the upcoming clashes against Liverpool and Aston Villa.

It is a big blow for Louis van Gaal, who is still without defenders Phil Jones, Rafael and Luke Shaw, during a crucial part of the season, where games come thick and fast.

Smalling has had a stop-start season, with recurring thigh and groin injuries and he didn't help his cause by getting sent off during the Manchester Derby, which caused him to miss more games for the club.

However, United will be glad that it is only a short layoff as the injury was not as bad as first feared. The England international should be back for the Red Devils' Boxing Day clash against Newcastle United.

The Dutch manager will be glad that he still has the services of first-team defenders Marcos Rojo and Jonny Evans, who are fit, as he gets his team ready for the highly anticipated clash against fierce rivals Liverpool.

Meanwhile, United winger Ashley Young, who has been deputising at left-back in the absence of Shaw and Daley Blind has praised striker Robin van Persie for his brace against Southampton. The Englishman believes that the three points and the return to form for the striker set it up perfectly for the visit of Liverpool to Old Trafford on Sunday.

"They were brilliant finishes from Robin. I think the first one was obviously a gift but he still had to finish it off. The second was one of those poacher's goals where he has worked on going around the back post and getting on the end of Wazza [Wayne Rooney]'s free-kicks. He managed to do that and we're just delighted to get the three points to take us into the next game," Young told United's official site.