Lukaku had to be stretchered off in United's 0-0 draw with Southampton after a clash of heads and was forced to miss Monday's 2-0 win over former club Everton.

But following tests and a return to training, the Belgian is now ready to return to action.

And Mourinho has confirmed Lukaku will make his comeback in Friday's FA Cup third-round clash with Derby.

"Romelu is back, Romelu is back," Mourinho told MUTV. 

"As I said it was not a concussion, it was a precaution, a protection for him. 

“He wanted to play against Everton, but this time he is back."

Mourinho also revealed Marouane Fellaini is fit to play after a month out.

He said: “From the injured players, Marouane Fellaini is back. 

“Antonio Valencia will be back to the team next week, so not playing tomorrow.

“Michael Carrick is back to training, not to competition, but is back to training with the team.”