The signing of Sanchez was meant to be their final forward arrival but the 29-year-old has so far flattered to deceive.
As a result, United may turn to other players as they aim to reel Manchester City in next season.
And Don Balon say Sanchez, and Jose Mourinho, are both talking to the player about a move.
Bayern have the option to sign Rodriguez permanently in the summer of 2019.
But, should United make parent club Real a sizeable offer, he may leave the Allianz Arena ahead of schedule.
GETTY
James Rodriguez: Bayern Munich star is 'in contact' with Alexis Sanchez about a Man Utd transfer
James Rodriguez scores his first Bundesliga goal for Bayern
Invalid email
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy
Bayern chief Karl-Heinz Rummenigge recently plunged Rodriguez’s future into uncertainty by saying: “We’re benefitting from his way of playing because he’s evolved into a playmaker.
“He’s on loan with Bayern for two years and then we have the option to buy him out of his contract for £37m, if I’m not mistaken.
“Of course, that’s still a lot of money, even if we all saw some really crazy figures during the last transfer window.
“We will wait and see what happens and decide what to do. However, that won’t happen in 2018 because we have plenty of time to decide and the purchasing option won’t expire.”