The £75million Belgian striker has joined fellow big-money signings Paul Pogba and Alexis Sanchez in growing frustrated under boss Jose Mourinho.
Lukaku, 25, would weigh up a move away from Old Trafford if his spell out of the team continues.
The new player crisis at United comes as Mourinho’s agent Jorge Mendes issued a statement claiming the Special One is “fully committed” to the club.
SunSport yesterday revealed United’s top brass want to replace him with Spurs boss Mauricio Pochettino next summer.
Mourinho is also the bookies’ favourite to become the next Prem manager to be axed.
But Mendes said: “Jose is very happy at the club and the club is very happy with him.
“He has a long-term contract with United and is fully committed to the club in building a solid winning project.”
Lukaku has started just two games since October and was back on the bench against Arsenal in midweek.
And it has been made clear Lukaku is no longer an automatic choice.
United chiefs are aware the Belgian is troubled by his spell on the sidelines.
He is on a long-term deal that would make it difficult to leave in January.
However, his agent Mino Raiola also represents Pogba and was trying to shift the France midfielder last season, according to City boss Pep Guardiola.
Meanwhile, Sanchez has been allowed to return to Chile to recover from a hamstring injury.
Source: Read Full Article