The Old Trafford full-back is a target for Juventus, with reports in Italy claiming he could now be on his way back to Turin, having left Torino for the Theatre of Dreams back in the summer of 2015.
Darmian has fallen down the pecking order once again and his agents at TMP Soccer will travel to Manchester shortly to meet with Mourinho.
The 28-year-old has made just four Premier League appearances this term and he has even seen winger Ashley Young preferred to him on the left hand side of the Red Devils' rearguard.
Sources close to the Darmian camp insist their man will jump at any chance to go to Juventus, with fears growing of him losing his place in Italy's World Cup squad.
United are hedging their bets on Darmian's immediate future, with club execs still trying to establish how successful they will be in acquiring a top-class replacement of their own next month.
The Italian is contracted until 2019 and United are acutely aware they will certainly struggle to recoup their original £15million outlay on the right-back.