Manchester United manager Ole Gunnar Solskjaer reportedly turned on Anthony Martial in the dressing room following Sunday's 1-1 draw with Chelsea.
The French forward was an unused sub at the weekend after recently struggling with a minor back injury.
According to the Daily Mail, Martial caused anger among United's backroom staff for his attitude before the match kicked off.
Martial was seen holding his hands behind his back and standing with one foot on a ball while his teammates went through a series of drills, which Solskjaer allegedly did not take kindly to.
Solskjaer is said to have vented his anger at the 23-year-old in front of the other players in the dressing room, accusing him of lacking effort.
The report indicates that there have been concerns over the ex-Monaco ace's attitude ever since he signed a long-term deal in January.