Pompey captain Tom Naylor is rated 50-50 to feature against Southampton in the Carabao Cup.
According to manager Kenny Jackett, the midfielder is struggling to play in the south-coast derby because of ‘a couple of knocks’.
The Blues now have a nervous wait over the former Burton man's fitness, with a decision to be made on Tuesday morning.
Naylor has played in 10 of Pompey’s 11 games this season.
He played in the centre of defence against QPR, Blackpool and Burton but returned to the Blues’ midfield for Saturday’s 1-0 defeat at Wycombe.
Naylor could therefore join Ellis Harrison in sitting out the first Pompey v Southampton derby since 2012.
The striker was sent off at Adams Park on Saturday and will now serve a one-match ban.
Jackett confirmed: ‘Tom Naylor has a couple of knocks.
‘He’s about 50-50 and we’ll see tomorrow morning.
‘After that, we’re selecting from the same squad.’