The 21-year old faced criticism from the Portuguese last season after missing games through injury.
"It's difficult for him [Shaw] to be on the bench. Why? Because I cannot compare him with Ashley Young, with Darmian, with Blind," said Mourinho of Shaw back in April.
"I cannot compare the way he trains and commits, the focus, the ambition. He is a long way behind."
The former Southampton starlet missed the majority of the 15/16 campaign and the last seven games of last season with ligament damage to his knee.