The Gills have been given extra time to prepare for the game following the postponement of their fixture against Northampton, giving Allen the opportunity to weigh up his options following their Boxing Day defeat to Barnet.
Allen's players were booed off the pitch after the 1-0 loss and his team are under extra pressure after losing their top spot to Port Vale.
Chris Whelpdale, Jack Payne, and Adam Birchall all made substitute appearances against the Bees and are first in line for a recall to the starting line-up.
Danny Kedwell, Ben Strevens, and Andy Frampton are further options available to Allen ahead of a stern test against their fellow promotion hopefuls.
The Kent club are seeking to improve their recent form which has seen them win only one of their last six games.
- Sports & Recreation
- Adam Birchall