Jackson limped out of the 0-0 draw with Stockport last time out with a hamstring strain, with Stimson being forced to check on the fitness of the 22-year-old closer to the game.
Defenders Simon King (ankle ligaments) and Barry Fuller (broken arm) are long-term casualties while striker Chris Dickson is unable to play under the terms of his loan from the Addicks.
Dickson's absence is likely to mean a starting place for Dennis Oli, who impressed when coming off the bench against County.
Gillingham have won just two of their last 14 league games as well as scoring only six goals since the turn of the year.
