The Scottish left-back played the entirety of the Reds' two fixtures in the league during the month, securing wins against Arsenal and Wolverhampton Wanderers.
Gallacher will compete with Adrian Bernabe (Manchester City), Teddy Jenks (Brighton and Hove Albion), Xande Silva (West Ham United) and Newcastle United pair Oisin McEntee and Yannick Toure for the accolade.
The shortlist was compiled by the Premier League’s football development panel after coaches picked out the best performance by an opposing player in their PL2 matches.