Pompey are unsure how long James Bolton’s latest injury will keep him out for.
The summer signing from Shrewsbury picked up an ankle setback against his former side on Saturday.
Replacing Anton Walkes in the 53rd minute, Bolton was on the receiving end of a nasty challenge from Shaun Whalley.
It caused the right-back to twist his ankle, although he was forced to play on as manager Kenny Jackett had already used up his full quota of substitutions.
Bolton will be sidelined for tonight’s Carabao Cup first-round tie against Birmingham, as well as the League One clash against Tranmere on Saturday.
It’s been a frustrating start to the 24-year-old's Fratton Park career, having missed the majority of pre-season with a groin complaint.
And the Blues’ medical team have unable to put a time frame on how long Bolton will stay on the treatment table.
When asked how long the defender will be absent for, Jackett said: ‘I don’t know, he certainly won’t play this week.
‘It's not one that our medical team can give me a time on.
‘I asked the same question but they’re not necessarily giving me a time.
‘They just said it's quite a nasty one. For James, it’s his second injury in quick succession but that'll settle down.
'They're not major injuries, which is good and he’ll get his opportunity because it’s early days.’