According to sources, Manek will take on the role of director of football operations at United.
His new responsibilities will include overseeing various aspects of the club's operations, such as travel, security, and staff management.
Manek will also be in charge of managing the Carrington training complex.
This move follows the departure of two other key individuals from Brentford to United: former coach Stephen Torpey, who became the new academy director, and striker Bryan Mbeumo, who joined the club over the summer.
Manek's appointment comes after the departure of David Harrison, who left United earlier this year as part of the club's cost-cutting measures.
