Sources at the club say rumours that first surfaced on Sunday night are wide of the mark.
Both the structure of the deal and Ederson's personal terms have long been agreed, United maintain, with completion originally pencilled in for July before a late World Cup call-up delayed matters, following an injury to Roma defender Wesley.
Ederson, who celebrates his 27th birthday on Tuesday, has already undergone an initial medical check, but United say a full examination will now follow with Brazil's World Cup campaign at an end.
Carlo Ancelotti's side exited the tournament at the last-16 stage on Sunday, beaten 2-1 by Norway as Erling Haaland struck twice.
Manchester United struck an agreement with Atalanta at the start of June worth £35million plus a further £3.8million in add-ons for the midfielder.
Since then, though, the club's efforts to bring in one or two further midfielders have stalled, having been beaten to both Elliot Anderson and Mateus Fernandes by Manchester City and Tottenham Hotspur respectively.
The search took a fresh twist on Sunday when it emerged that Ederson's compatriot Andrey Santos has entered United's thinking as a potential alternative target.
United have registered their interest in the Chelsea midfielder, aware he could become available having slipped behind Enzo Fernandez in the pecking order at Stamford Bridge.
That interest remains at an early stage, however, and no contact has yet been made with Chelsea over a potential deal.
For now, completing the Ederson transfer remains United's immediate priority, with the Brazilian expected to undergo his full medical in the coming days now his international commitments are done.
Ederson has been a key performer for Atalanta in recent seasons, and his move to Old Trafford is meant as a statement of United's ambitions this summer.
The delay caused by his late World Cup selection was always expected to push back the closing stages of the deal rather than threaten it altogether, sources close to the negotiations say.
United's broader search for midfield reinforcements has proved trickier, having twice been beaten to targets by direct Premier League rivals this summer.
Missing out on both Anderson and Fernandes has left United still hunting for further additions, explaining the growing focus on Santos as a potential option.
Chelsea's valuation of the 22-year-old is likely to prove decisive if United's interest develops further, given Santos only nailed down a regular starting role last season.