The Blues are out to make it 27 League One games unbeaten, but face an opponent who’ve won 10 of their last 11 visits to Fratton Park.
It appears something has to give with John Mousinho having injury and selection issues to contend with going into the game.
This is how we think he’ll go as he welcomes former Pompey boss Michael Appleton’s side to PO4.
13. Sub 2: Zak Swanson
Another really impressive showing against Orient and has a strong case to say he should start. Undoubtedly got an important role to play this season. Photo: Jason Brown
14. Sub 3: Ryley Towler
So, so impressive on Tuesday night and the fact he took the captain's armband when Sean Raggett was sent off says a lot - at the age of just 21, too. Could start alongside Shaughnessy in a rejig, but the bench most likely. Photo: Jason Brown
15. Sub 4: Terry Devlin
Has upped his involvement in recent weeks, but may be the time to sit back after a busy flurry of first-team activity. Photo: Jason Brown
16. Sub 5: Marlon Pack
The news of the skipper being back in training and available for selection has been a refreshing boost after injury setbacks. Seems sensible to ease him gently. Photo: Jason Brown