The 21-year-old got his first team debut last season, impressing in his first season under the Portuguese, but with just four appearances under his belt and an underwhelming performance this campaign, his development seems to have stopped at the moment.
The Scottish youngster has struggled to get going this term, with Mourinho slating him after he had a shocker in the 3-2 win over Newcastle. But it is understood that Mourinho still wants to give him further chance to improve his game. The Old Trafford hierarchy too are believed to be happy with the idea of letting the player join the right club on loan in January as they hope it will tighten up the player more.
The youngster is thought to be linked with Championship side Leeds and Aston Villa at the moment and United are ready to let him leave in January to the side which would promise to give him more game-time.
A move to Leeds would give the youngster a chance to work under tactical genius Marcelo Bielsa, who has steered the Lilywhites to third in England's second tier at the moment while a move to Villa would see him working with former Brentford boss Dean Smith who was appointed as the successor to the recently fired Steve Bruce after he failed to win last 11 matches.
Nevertheless, whatever move the player chooses, it will certainly be beneficial to the player as at the moment it looks like the player is still not ready for Premier league's first-team football. Moreover, at United, he has to face competition with the likes of Fellaini, Fred, Matic and Pogba which can certainly effect his playing time.