Steve Cotterill will be forced to make one change to his side after they beat Norwich last time out.
Greg Halford is suspended for one game after picking up his ?fth yellow card of the season.
But Carl Dickinson returns from a three-match ban after his red card against Doncaster on November 13.
That should see Joel Ward shifted over to right-back, with Dickinson on the left.
Both Michael Brown and Richard Hughes are available to play one more game each amid their contract negotiations.
Defender Joel Ward said: 'Up there earlier in the season was a tough game. We came under the cosh late in the second half and dealt with it well and showed courage.
'Hopefully, we can show that again and go on to win the game.
'It's always frustrating when matches are called off like they have been recently.
'We want to play as many games as we can so it is a nightmare really.
'It's not very nice and disturbs the run we are on.
'This is a big month for us and we can close the gap between the top six and the top two.
'We want to keep playing and are in good form as well.
'It's my first season playing regularly over Christmas so I'm looking forward to it.'
Skipper Paul Robinson is set to miss Millwall's trip to Pompey.
Robinson has picked up a hamstring injury, which will keep him sidelined.
The only other missing player for the Lions will be long-term absentee Shaun Batt, who suffered medial ligament, cartilage and hamstring injuries in a pre-season outing.
Kenny Jackett has to decide between Nadjim Abdou and Liam Trotter.
New signing Josh McQuoid is looking for his first goal since signing on loan from Bournemouth.
Lions boss Kenny Jackett said: 'You know that you are going to be in a difficult game when you go down to Portsmouth's Fratton Park.
'They will have a good crowd there who will get behind their team.
'But we will have a decent following and we are going there to give them a real tough test.
'There is quality in Steve Cotterill's squad, there's no doubt about that.
'They have had a lot going on behind the scenes there recently but things seem to be settling down a bit more now for them.
'We are going into the game in good form, though, and if we apply ourselves properly there's no reason why we can't keep that going.'