Priestfield Stadium hosts a contest between two sides at opposite ends of the League One form table on Saturday (3pm kick-off).
Pompey impressed in their 3-0 victory at Lincoln earlier in the week – a fifth successive win that extended their unbeaten run to eight games.
Danny Cowley’s men remained ninth in the standings after that result, but closed the gap on the play-off spots to just three points.
Gillingham, meanwhile, are down in 20th position and looking to avoid dropping into the relegation places.
They have not won a game in any competition since a 1-0 home success against fellow strugglers Doncaster in mid-October.
It is a sequence that has seen them collected just three points from a possible 15 and exit both the FA Cup and Papa John’s Trophy.
There is also uncertainty surrounding the future of experienced manager Steve Evans, who is wanted by League Two outfit Stevenage.
Pompey collected four points against the Gills last season, with John Marquis and Michael Jacobs on target in a 2-0 triumph in Kent.
Sean Raggett is serving a one-match ban after collecting his fifth booking of the season at Sincil Bank – just before an amnesty kicked in.
There is a doubt over the availability of John Marquis, who has been struggling with a tendon problem.
Skipper Clark Robertson (hip) is joined by Paul Downing (calf), Jayden Reid (knee) and Ryan Tunnicliffe (hamstring) in the treatment room.
Gillingham are missing Kyle Dempsey (knee), Alex MacDonald (knee) and Vadaine Oliver (ankle), while Rhys Bennett and Danny Lloyd are both carrying knocks.
Former Fratton loanee Stuart O’Keefe is available again for the hosts, however, after completing a one-match suspension.
HEAD TO HEAD
Pompey: 20 wins
Gillingham: 9 wins
At Priestfield Stadium
Pompey: 8 wins
Gillingham: 7 wins
Tickets are no longer on sale and cannot be bought at Gillingham on the day of the game. Collections will be from the away turnstiles on Priestfield Road.
Referee: Dean Whitestone
Assistants: Michael George and Akil Howson
Fourth Official: Charles Breakspear
Domestic iFollow subscribers can listen to live commentary from Andrew Moon and Guy Whittingham by signing into their account and visiting the match centre from around 2.45pm on Saturday.
Overseas subscribers and match pass holders can watch the action and commentary will begin from around 10 minutes before kick-off.
There will be post-match reaction on the website and our official YouTube channel, with highlights to follow on Sunday.
ALSO IN LEAGUE ONE
All games kick-off at 3pm
AFC Wimbledon v Fleetwood
Bolton v Cheltenham
Burton v Doncaster
Cambridge v Sunderland
Lincoln v Accrington
Morecambe v MK Dons
Oxford v Rotherham
Plymouth v Wigan
Sheffield Wednesday v Wycombe
Shrewsbury v Charlton
Ipswich v Crewe