The 27-year-old is moving to the Owen Street Sports Ground until the end of Coalville’s campaign on Saturday April 22.
He has scored once in 31 appearances since joining the Pilgrims from Grimsby Town.
Marshall is the fifth United player currently out on loan — with Courtney Wildin (Corby Town), Waide Fairhurst (Frickley Athletic), Callum Chippendale (Gainsborough Trinity) and Joe Maguire (Buxton) completing the quintet.