Romelu Lukaku suffered a head injury in the opening stages of Manchester Uniteds match against Southampton.

The forward was taken off on a stretcher in the 12th minute after colliding with Saints defender Wesley Hoedt and is thought to be out of action for some time.

It is understood the forward was treated at the ground as the doctors went through the concussion protocol, which could mean the striker misses United's next two ties.

If the striker did lose consciousness he would be forced to the sidelines for at least six days- per the FA protocol- meaning he would miss the trip to Everton and the FA Cup tie against Derby.

According to AP reporter Rob Harris , Mourinho confirmed the forward would be out for a while and also confirmed he would be without natural replacement Zlatan Ibrahimovic.

After the game, Mourinho said: 'Zlatan one month out. I don't know, I really don't know (if Manchester United need reinforcement), but I'm happy with the players' attitude with the players' desires and I have no complaints about my players.'

United players looked immediately concerned for their teammate after what seemed an innocuous challenge for the ball.

But replays showed Hoedt made contact with the back of Lukaku's head, albeit unintentional.

The forward fell to the floor and looked to be in trouble, with a vacant expression on his face as United's team of doctors tended to him.

A stretcher was brought on and the striker eventually left the field after being carefully monitored by the medics.

The Southampton defender was unharmed after the incident with it appearing to be the position of the blow, rather than the force, which harmed the striker.

Mourinho quickly identified a problem and ordered Marcus Rashford to warm up as a replacement.

The boss had previously said his forward was feeling the effect of so many games but acknowledged Lukaku's desire to play.

Credit: Dailymail