The Reds' youngsters will provide Alty's final opposition before their National League campaign kicks off, with the game starting at 15:00 BST.
The J. Davidson Stadium, formerly Moss Lane where United's Reserves used to play home matches, will host the fixture.
The match takes place the same day as the first team are in action in Oslo against Atletico Madrid, and a day before the recently announced Old Trafford friendly with another side from La Liga in Rayo Vallecano.
The Under-23s should benefit from being able to call upon members of the successful FA Youth Cup-winning side, with some of Travis Binnon's youngsters already blooded at Premier League 2 level.