Paul Cook is targeting an experienced central defender to fill the gap created by Paul Robinson’s exit.
The 33-year-old left the Blues by mutual consent on Friday – and is set to sign a two-year deal at AFC Wimbledon.
Sometimes fans look for stuff that just isn’t there, unfortunately I can’t keep everyone happy and I am certainly not going to try. The only ones I have got to keep happy in general are the people who come to Fratton ParkPaul Cook
It leaves Pompey with only Christian Burgess and Adam Webster as central-defensive options, with Jack Whatmough ruled out until Christmas.
In addition, Matt Clarke’s long-anticipated loan move from Ipswich Town is set to be confirmed today.
But Cook is also eager for a more experienced arrival in that department.
He said: ‘We will like to have another in, of course we would, in addition to Clarke when he gets over the line.
‘But it’s hard sometimes because a lot of lads want to play and you have got to be careful as a manager.
‘How many players can you guarantee to play?
‘Matt (Clarke) is going to be a really good player, he is 18 years of age and plays like a man.
‘If we were to get him over the line, that is great.
‘Then you’ve got big Christian Burgess, Adam Webster, while Jack is going to be back around Christmas.
‘Of course we are going to need experience, but sometimes you are looking for experience who might be happy to not play, they aren’t easy to find.’
Robinson netted for Wimbledon on Saturday just 82 seconds into his maiden appearance as he helped his new club to a 3-1 victory over Cheltenham.
With Pompey unable to offer regular first-team football, Kingsmeadow will now be the 33-year-old’s home.
Cook added: ‘Football is a short life-span for everyone, Paul is a smashing lad, a good lad to work with.
‘Sometimes fans look for stuff that just isn’t there, unfortunately I can’t keep everyone happy and I am certainly not going to try.
‘The only ones I have to keep happy in general are people who come to Fratton Park.
‘When you get to an age like that, looking to the future is important.
‘We wish him and his family the best of luck in the future.
‘Natural progression happens at a club like ours – where we finished last year in the league is not good enough is it.
‘For all of us – fans and managers – there mustn’t be an acceptance and certainly there is no blame to a single player.
‘My job is hopefully to change the culture of a club towards where I believe it can go and certainly what the fans believe.’