The Daily Telegraph (h/t Metro) reported the trio have failed to make their mark under manager Jose Mourinho, who must clear out some of the current squad before he can make upgrades in the full-back positions.
Shaw is yet to make a Premier League appearance for the Red Devils so far this season, while Darmian and Blind have earned a combined five league starts between them.
It's possible one or more of the three could leave Old Trafford in January, although BBC Sport's Simon Stone recently said Shaw is one whose fate will be left until the end of the season:
Mourinho has taken to splashing the cash on specialists in certain areas since his arrival, but the full-back slots have remained without investment since his 2016 arrival.
That's left the Portuguese with converted midfielder Ashley Young as his first-choice at left-back, while Antonio Valencia has held down his spot at right-back almost unopposed.
United's reserves have been Shaw's main source of playing time this season, and blogger Liam Canning recently put forward a potential swap solution to the left-back quandary:
All three players were brought to the Theatre of Dreams by Mourinho's predecessor, Louis van Gaal, but none have managed to carve out reputations for themselves as frequent figures under their Portuguese boss.
Blind can offer cover at left-back and in central defence, while Darmian has operated on both flanks, but that didn't prevent ESPN's Alex Shaw from criticising the Italian's tenure as a United player:
None of the trio were named in United's squad for Saturday's 1-0 win over Brighton & Hove Albion despite all being fit, a signal as to how far down they sit in the club's pecking order.
It's unlikely Mourinho will be able to make the upgrades he desires until the summer transfer window, but a clearing-out of some players deemed surplus to requirements will lay the path for new arrivals.