Dave Kitson and Aaron Mokoena are both pushing for instant recalls to the Pompey side after serving suspensions.
Kitson looks likely to come straight in for John Utaka, who left the club to join Montpellier over the weekend, while Mokoena could replace Ibrahima Sonko in central defence.
Loan signing Jonathan Hogg is expected to retain his place in midfield, while Jamie Ashdown, Hayden Mullins and Ritchie de Laet have all recovered from their respective knocks and are expected to start.
Boss Steve Cotterill said: ‘It’s not all about Adel Taarabt – they’ve got other players who are just as vital to them.
‘We know that the boy has got ability and we need to keep a watchful eye on him.
‘They have a big, strong, healthy squad where they can cope with any loss of form, loss of confidence or injuries.
‘Players like Shaun Derry and Clint Hill are good guys who have been around for years.
‘We’ve got to make sure that we focus on our own job.
‘It’s also about how well we play and what we do.’
Pompey old boy Tommy Smith is struggling to face his former club after picking up a hamstring problem in the draw with Hull City at the weekend.
Alejandro Faurlin and Heidar Helguson are also battling injuries, so Rob Hulse and Ishmael Miller are on standby, while Norway international Petter Vaagen Moen is set to replace Faurlin.
Akos Buzsaky, Peter Ramage, Jamie Mackie and Patrick Agyemang are all long-term absentees, while Danny Shittu and Pascal Chimbonda are both pushing for debuts.
Rangers boss Neil Warnock said: ‘I’m disappointed and frustrated we failed to beat Hull on Saturday, now we must look to put that right tonight.
‘I was surprised how Hull set their stall out – put the bus in front of the goal.
‘I felt we dominated the game for 80 minutes. I just thought the last 10 minutes they had a little bit.
‘We could have done a lot better in the last third, we didn’t test the keeper enough.
‘Now we have Portsmouth and it will be a difficult match.
‘They gave us a good game at their place and tonight will be no different.’