Earlier this week, reports in France claimed the 22-year-old is at odds with Jose Mourinho due to his lack of playing time this season.
Alexis Sanchezs arrival has meant increased competition in Martials favoured position and the France international has been an unused substitute in Uniteds last two fixtures.
Reports have claimed that Martial is unhappy at Old Trafford and will look to leave at the end of the season with Juventus and Tottenham interested in a deal.
Martials discontent appears to have been picked up by the rest of his United teammates, judging by Uniteds latest promotional video.
Lukaku was tasked with describing United players to his teammates, who then had to guess the player the Belgian was referring to.
And when it came to describing Martial, Lukaku bluntly said: French, never happy.
Sergio Romero and Eric Bailly instantly knew the striker was referring to Martial and immediately named the French forward, much to the delight of Paul Pogba.
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