The Lions will head into the midweek round of fixtures in eighth position, while Pompey are languishing in 23rd place in the Championship table.
Match preview
Portsmouth are still waiting to play their first game following the international break after Saturday's away meeting with Blackburn Rovers was postponed due to a waterlogged pitch.
Following the postponement, Pompey boss John Mousinho would have quickly turned his focus to Wednesday's home fixture against Millwall, with his side keen to build the victory they recorded in their most recent outing against Preston North End.
On that occasion, Josh Murphy, Conor Ogilvie and Colby Bishop all got on the scoresheet to fire Pompey to a 3-1 victory, representing their first home win of the season.
Pompey will have to start picking up wins on a more consistent basis if they are to close the four-point gap to safety and avoid an immediate return to League One.
However, their hopes of claiming all three points against Millwall may be tempered by the fact they have failed to win their previous five head-to-head meetings (W4, D1) since they picked up a 1-0 away victory in October 2010.
In contrast to their hosts, Millwall are operating in the top half of the table after winning six, drawing six and losing four of their 16 league matches.
The Lions have proven to be a tough team to beat in recent times, having put together an eight-game unbeaten run since they lost to Cardiff City at the start of October.
Neil Harris's side kicked off that encouraging run of form with back-to-back draws, before they recorded four consecutive 1-0 victories.
After playing out a 1-1 draw with Stoke City before the international break, Millwall went on to repeat that scoreline in Saturday's away clash against Sunderland, with Femi Azeez netting a 93rd-minute winner to extend his team's unbeaten streak.
Millwall, who are two points adrift of the playoffs, will now look to continue their impressive record against Portsmouth, having won each of their previous four competitive meetings, including a 1-0 win in August's EFL Cup clash at Fratton Park.
Portsmouth Championship form:
W
L
L
D
L
W
Millwall Championship form:
W
W
W
W
D
D
Team News
The hosts will also be without the services of Jordan Williams and Ibane Bowat due to hamstring and knee injuries respectively.
Mousinho recently revealed that Conor Shaughnessy will be out for the rest of 2024 after picking up another calf issue in training.
Bishop could be given more valuable minutes off the bench after he made a surprise return following heart surgery to score in the 3-1 win over Preston.
As for the visitors, Harris has confirmed that defender Jake Cooper will be sidelined for around 10 weeks due to a knee injury.
Calum Scanlon is also expected to miss the away trip, while Josh Coburn will have to be assessed after he appeared to pick up a knock at the weekend.
Billy Mitchell and Adam Mayor are closing in on a return to fitness, but it remains to be seen whether either of the pair will be ready for Wednesday's away trip.
Portsmouth possible starting lineup:
Schmid; Devlin, Poole, Pack, Ogilvie; Potts, Dozzell; Ritchie, Lang, Murphy; Yengi
Millwall possible starting lineup:
Jensen; Leonard, Hutchinson, Tanganga, Bryan; Saville, De Norre; Esse, Coburn, Azeez; Bradshaw