According to Kris Voakes of Goal, the Red Devils have been keeping tabs on Lucas for a while, as he's fallen down the pecking order at PSG.
It's added United "have yet to make a formal bid for the Brazilian, but they have been in touch with his advisors over a significant period of time, having originally targeted the player as a 19-year-old when he was still playing in his homeland with Sao Paulo."
Additionally, it's also been reported by UOL (h/t Lucas Sposito of Sport Witness) that United have reached out to Lucas' representatives through intermediaries. It's added a "positive outcome" is expected to emerge between Lucas and the Red Devils.
Bleacher Report's Rob Blanchette believes the former Sao Paolo man would be a smart addition for the Red Devils, though he would prefer a temporary deal:
As noted by Voakes, United were close to bringing Lucas to Old Trafford in 2013 before he opted to make the switch to Paris.
Since that switch, Lucas has failed to go on and accomplish what was expected of him and, now 25 years old, appears in need of a new challenge. This season he's yet to start a single top-flight game for PSG.
The winger has been bumped to the fringes after the summer arrivals of forwards Neymar and Kylian Mbappe. However, as relayed by journalist Adam Joseph, when he has got on the pitch he's tended to make things happen:
Indeed, Lucas is a live wire when he's in the mood. The Brazilian is a strong runner and supremely skilful, and his blistering pace constantly leaves opposition defenders on the back foot.
What's let him down throughout his time at PSG has been inconsistency; he's never quite been able to nail down a first-team berth under a number of managers. Now his spark is in danger of fizzling out and he requires a new start to reignite it.
United would potentially benefit from another wide man, and Lucas would undoubtedly bring something different to either flank. Per Rob Dawson of ESPN.com, often Jose Mourinho's side rely on full-backs to provide penetrative threats from the wing:
Indeed, while Jesse Lingard, Anthony Martial and Marcus Rashford have all been used as wingers, they'd all prefer to play infield, supporting a forward or at the point of the attack. Lucas, while he has operated centrally in his career, loves to hug the touchline and test out full-backs.
As relayed by Sport Witness, Le Parisien reports the Ligue 1 leaders want a fee of €40 million (£36 million) before they complete any deal for Lucas, an amount the player is said to feel is excessive.
Given his lack of football and subsequent fading reputation, you sense United may be reluctant to pay so much. However, if they can negotiate a cheaper deal, then Lucas is a player that may well be worth taking a gamble on.