The centre-back will begin a two-match ban after collecting his 10th booking of the season in the goalless draw with his former club Carlisle last time out.
An unnamed player has also been ruled out by Stimson after sustaining a knee injury in a minor car accident.
But the Gills have been boosted by the news that Matt Fry has extended his loan from West Ham by a further month.
On-loan striker Febian Brandy (thigh) is responding well to treatment after returning to parent club Manchester United earlier this week, but he has yet to resume training.
Long-term absentees Danny Jackman (shoulder) and Simon King (ankle ligaments) remain on the sidelines.