Ndiaye, 26, is understood to be open to leaving and his camp would welcome an approach from Al-Hilal, who have already brought in Crysencio Summerville from West Ham this summer and are keen to add another attacker.
The Saudi club's interest is thought to have been helped by Ndiaye's close friendship with former Everton team-mate Idrissa Gueye, a fellow Senegal international who has himself recently moved to Saudi Arabia, though Manchester United remain firmly in the picture, with left wing among Michael Carrick's priority areas this window.
The Mirror reports that Everton are aware of Al-Hilal's interest but that no talks have yet taken place between the clubs, with the Toffees expected to hold out for a fee similar to the £70m Barcelona paid Newcastle for Anthony Gordon.
Ndiaye joined Everton from Marseille for around £17m in the summer of 2024 and has since become one of the club's most productive attacking players, scoring 10 goals without registering an assist in his debut season before following up with six goals and three assists last term.
He also impressed for Senegal at this summer's World Cup, contributing a goal and two assists across 127 minutes. With three years still to run on his contract, Everton are in no rush to sell, but the scale of interest from two directions, Saudi riches on one side and Premier League ambition on the other, means a departure this summer cannot be ruled out.
Ndiaye has come to the forefront of Manchester United's thinking after Morgan Rogers instead joined Chelsea for £117m and Yan Diomande signalled his preference for a move to Real Madrid, though the Red Devils' need for a left winger is not viewed as especially urgent, with Marcus Rashford due to be reintegrated into the squad following a season on loan at Barcelona.