The Portuguese suggested the left-back was a fault for Watford's second goal in United's 3-1 defeat at Vicarage Road on Sunday, which came two minutes before the 21-year-old was hooked.
Mourinho's public negativity towards Shaw has been slammed by many pundits including former Arsenal captain Keown.
“At 21, Shaw is an easy target for Mourinho and would have been humiliated at being substituted immediately after the goal.
“He has the potential to be one of the finest left backs this country has ever produced, but he's playing with no confidence. His main strength is to tear forward at any opportunity, but it looks as though Mourinho has him playing in a straight-jacket."