The 22-year-old has been a fringe player under Jose Mourinho, despite demonstrating a clear knack for goals in brief stints off the bench.
It's been stop-start since then though with the Frenchman coming in and out of both Louis Van Gaal and Jose Mourinho's sides.
With Mourinho generally favouring consistency amongst his attacking players, the tendency with which Martial blows hot and cold may well see him sacrificed in favour of a more suitable candidate.
Martial's return of 24 goals in 82 appearances is good but not spectacular while his struggles to get regular game time have not helped.
The attackers current contract expires in 2019 and while United have an option to automatically extend the deal until 2020, the newspaper says talks over a new long-term contract have stalled after Martial rejected the clubs latest offer.
His lack of playing time is the main reason for the refusal according to RMC Sports.
Martial has become increasingly frustrated at losing his spot to Alexis Sanchez, who arrived from Arsenal in the January transfer window.
It is believed that top teams including Juventus, PSG and Tottenham are all gearing up for his signature if at all he will request to leave.
United would be reluctant to sell to Spurs but any of the other three clubs could easily come up with the €60 million fee United would be likely to demand in the event of Martial's departure.
Bale, whose preferred position on the right would be flawless for United, has fallen out of favour at Real and is believed to be considering his future at the club, with the likes of Lucas Vasquez and Marco Asensio now ahead of him in Zinedine Zidane's plans.