The Red Devils have entered negotiations to sign the Brazilian but a severance package owed to the player by Lazio could leave them waiting until late in the month
Goal understands that the Brazilian has been identified by United as one of their key targets in the January transfer window, and negotiations involving executive vice-chairman Ed Woodward began in December.
But it has now emerged that the 22-year-old is in no rush to leave the Stadio Olimpico without a bonus payment promised to him as part of his buyout clause.
Anderson has a stipulation within his contract which compels Lazio to accept any bid over £35m, and he is due a small percentage of the fee as part of an agreement made with the club.
However, initial indications from Lazio have suggested they would not be willing to immediately hand over the severance package, with the player deciding to wait before making a decision on the United transfer until his current club have made a final decision relating to the payment.
Lazio sporting director Igli Tare admitted on Wednesday that his club will “evaluate every offer” for their players during January, giving United a clear run at Anderson.
The Brazilian was then substituted at half-time of the disappointing 0-0 Serie A draw at home to Carpi on Wednesday afternoon following an underwhelming first 45 minutes.
Following the game, Lazio manager Stefano Pioli was questioned about United's pursuit of the midfielder but gave nothing away, saying: "It is up to the board to make certain decisions in the market"