Pompey are seeking a right-back replacement for Nathan Thompson.
Kenny Jackett has initiated a contingency plan should the 28-year-old decide not to return to Fratton Park for contract talks.
Thompson, who next month becomes a free agent, is presently reviewing his transfer options.
Keen to test himself in the Championship, the opportunity to experience that with the Blues was ended through last week’s play-off elimination.
Jackett, though, remains eager to retain his first Pompey signing, with a contract offer still on the table.
Yet the Blues are actively seeking an alternative should Thompson elect not to return.
The Fratton Park boss said: ‘We are looking at replacements and, as it goes along, you have to assess how long you wait.
‘If you have the opportunity to get a replacement, you need to know whether that is likely or not.
‘We are looking and talking to people that play in that position, definitely. We are not close to signing one, but are out there looking for the right one.
‘Nathan is going to review his options. As time goes on, he will know we are looking as well.
‘He definitely knows he is welcome to stay here, 100 per cent. If and when he wants to come to the table he can, he knows that.
‘He has gone away for the summer with a very, very good relationship with everybody here, and a very clear one as well.
‘We know the minute he wants to talk to us then he’ll be in touch. Similarly, we are not naive, it has got to this stage, it looks like we will need a replacement, and obviously we are actively looking.
‘He is welcome to stay, he knows that, we would like to see him next year, but obviously we have got to this stage and have to be realistic and look at other options.’
Thompson arrived in June 2017 on a free transfer from Swindon.
He subsequently established himself as first-choice right-back under Jackett, making 78 appearances and scoring once.
Pompey, though, are unsure on their chances of keeping him.
Jackett added: ‘It’s hard to tell, I haven’t read anything or heard anything, I presume he is reviewing his options.
‘But I wouldn’t know that having not spoken to him this week.
‘For us, it depends what comes up. If a fantastic right-back comes up then we have a decision to make.
‘At the moment we are not necessarily close to signing anybody, but are we summing up our options for another right-back to compete with Anton Walkes in that position?
‘Yes we are.’