The striker, on a season-long loan from Nottingham Forest, has scored six times so far in what has been a difficult season for Gillingham.
The Kent club were relegated from the Championship alongside Forest last season, after drawing their final game of the campaign 2-2 at the City Ground while Crewe were beating Coventry.
Harris is suspended for Saturday's trip to the City Ground although may not have been allowed to play against his parent club anyway.
The game is a rare chance for Forest to complete a double this season. The Reds 3-1 win at Priestfield in August was their only away win until last month's triumph at Port Vale.