The reason for this was Jose Mourinho's desire to keep the youngster as an option for the rest of the season.
This is quite simply because nothing has changed at Manchester United in the past fortnight, in fact McTominay is even more important.
Manchester United's lack of depth in midfield was exposed against rivals Manchester City with star man Paul Pogba suspended.
It would only take one or two injuries to elevate McTominay into a more prominent role, and the fact he has already featured in the Champions League this season speaks volumes as to Jose Mourinho's faith in him.
Unless the Red Devils go out and sign a midfielder in January, they need to keep McTominay around for squad depth, and not loan him out to Leeds.
There is no guarantee McTominay would be used regularly at Leeds given their plethora of midfield options, and there's quite simply no need for Manchester United to change their stance, having already given a 'no' to Rangers.