The midfielder, 26, is is still on the books at Old Trafford - despite having not featured for United in a competitive match since the 2019-20 season.
The Brazilian side have an option to make the deal permanent for £17million.
But club vice-president Marcos Braz has confirmed that they want to get him cheaper.
Braz, as well as other Flamengo top brass, flew into England today to try and negotiate a deal.
Prior to travelling, he told Canal FlaZoeiro: "The trip is mainly to see Andreas' situation.
"Let's try to buy the player and sit on the negotiation.
"We can't wait until the end to find out what will happen.
"Let's understand what the English want and hope that everything works out."
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