Romelu Lukaku
Romelu Lukaku is Manchester United's leading goalscorer this season Reuters

Manchester United manager Jose Mourinho has confirmed Romelu Lukaku will be sidelined for a week.

The Belgium international was stretchered off the field after suffering a head injury in the Red Devils' goalless draw against Southampton. The Saints player Wesley Hoedt headed back into the former Chelsea striker's head, following which he received extensive treatment close to six minutes before being carried away on a stretcher.

Mourinho had already confirmed that Lukaku will miss the clash against his former club Everton and also the FA Cup third round tie against Derby County at home. The Portuguese tactician has now confirmed that he expects the striker to be out of action for a week.

"I would say a week [out for Lukaku]. It's nothing really important - just a little protection, but no problem," Mourinho told Sky Sports, as quoted by United's official website.

United are also without last season's top scorer Zlatan Ibrahimovic. The former Barcelona and Paris Saint-Germain, who returned from a long-term injury, has suffered a knee injury. He is expected to be out of action for a month.

This has left Mourinho with Anthony Martial and Marcus Rashford as the other players, who can play as a centre forward. Mourinho started the Frenchman in United's 2-0 victory over Everton on 1 January.

The former Real Madrid and Chelsea manager stressed that his men have to adapt in the absence of Lukaku and Ibrahimovic.

"Of course. If we don't have a player like Lukaku or a normal replacement like Zlatan, we have to play with the qualities we have, so we have to forget that we have to play without a target man because we don't have [one]," United manager stressed.

"We have what we have. We trust the players. The players are giving everything like they have done from the first minute of the season. No Lukaku and no Ibrahimovic means we have no no.9 as you normally call a target man that we usually play [with], so we have to change."