The Chilean is believed to be unhappy at Old Trafford and looking to leave the club, having lost his place in the side to Anthony Martial and scored just one goal in all competitions this season.
Mourinho has been stumped by his sudden decline in performances, and The Times claim he has privately admitted that United signed the wrong winger.
The Portuguese coach still regrets the clubs failure to sign Perisic – with CEO Ed Woodward reportedly refusing to stump up an extra £5m – and believes his skillset would have been a better fit.
Mourinho feels his side lack a brilliant crosser to exploit their height advantage and has been disappointed with Sanchezs end product.
Perisic would have offered superior crossing ability, while there is also a sense that he would have been more accepting of the style of play promoted by Mourinho.
Sanchez has not taken to Mourinhos management style and, according to The Times, some of his teammates believe he gets intimidated by the managers dressing downs after defeats.
Even though Sanchez impressed against Juventus last time out, Mourinho is also unhappy with his goal return.
The United boss believes he should be far more prolific than he is and now considers him firmly behind Anthony Martial in the left-wing pecking order, with the Frenchman having scored five goals in his last four Premier League appearances.
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