The Portuguese is preparing to make changes to the squad he has inherited from Louis van Gaal which has prompted an enormous amount of speculation regarding his ins and outs this summer.
According to former Red Devils striker Yorke, there are only four current United players who will be left alone in the end-of-season transfer window as Mourinho strives to return to then club to former glories.
"Everyone is jumping on the bandwagon but it's just rumours in the media," Yorke told 88sport.
"We obviously know about (Juan) Mata and Jose and that hasn't changed.
"There will be a few players under the microscope who aren't Manchester United players who somehow got in there.
"They've underperformed and no-one is safe apart from (David) De Gea, (Anthony) Martial, (Marcus) Rashford and (Wayne) Rooney. Everyone in between will be looking over their shoulders."