Pompey are waiting to learn the full extent of injuries to Tom Naylor and Sean Raggett.
But Ellis Harrison is expected to be available for the Blues’ next match at Rochdale following a sore back.
Anton Walkes was employed to stand-in for Naylor in a holding-midfield role, partnering Ben Close.
While Paul Downing came off the bench to replace Raggett at the heart of Pompey’s defence.
Kenny Jackett said: ‘Tom Naylor is a very robust player, we hope it’s not too bad, but he felt his hamstring straightaway.
‘He has felt it and gone down, which is unlike him.
‘The injuries are muscle injuries to players quite robust in that area and that suggests they won’t be out for long.
‘Hopefully it’s not too long, but it’s difficult to tell at the moment.’
Meanwhile, Harrison didn’t travel with the Blues for the first-round clash.
Jackett added: ‘Ellis aggravated his back and it kept him out last night, hopefully by the time games come around with Rochdale and Rotherham he will be available to us.
‘It happened around about Friday, he had a very sore back and we then didn’t take him down to the Astroturf on Saturday and didn’t bring him yesterday.
‘It’s the type of injury which can go away pretty quickly, we are hopeful for a week on Saturday (Rochdale).’