The Portuguese winger has been a peripheral figure at old Trafford for some time, with former manager Sir Alex Ferguson and current chief David Moyes having grown frustrated with his hot and cold form.
With United ready to make serious moves in the transfer market in the coming windows, Nani has been linked with an exit before the current deadline passes, with a loan move back to Sporting Lisbon having been mooted.
However, Fulham boss Rene Meulensteen is ready to hijack the switch.
The Dutchman is desperate to add proven quality to his side in a bid to avoid relegation, and has made a player capable of providing his talented strikers with service a priority.
Having worked with Nani while in a coaching role at United, Meulensteen is convinced that the wide-man is just the player he needs, and is ready to offer him a Premier League lifeline with a temporary deal.
The Red Devils are likely to be open to the idea, with regular action potentially enough to see the winger’s value rise ahead of a possible future permanent transfer.
Ruiz has been unable to make an impact in West London this season, and is close to sealing a move to PSV Eindhoven.