According to the Blues’ chief executive, a number of players and representatives whose contracts expire in six months’ time have been approached.
Such individuals have been advised there will not be an extension on the table.
That puts the spotlight on John Marquis, Paul Downing, Ellis Harrison and Callum Johnson, in particular.
And Cullen explained how talks are already underway to remove unnamed members of the squad from the wage bill.
He told The News: ‘Will players leave? I don’t know at the moment.
‘There are clearly discussions which may have gone on on an individual basis with certain players.
‘But you’ve got to make sure you are not going to weaken your numbers. If you can’t put a team out at the moment, that is going to continue into January.
‘We would look to rejuvenate some positions where we possibly can, we know the positions we’re weak in and that’s where we have been working on.
‘At the moment, Danny is working on the basis where he wants his group to be together.
‘There may be players that will want some sort of clarity over what their future could hold beyond the end of the season – and those sorts of discussions have been taking place.
‘That is as broad as you’d want to go at this stage because it will depend very much on those players.
‘They have a contract with us until the end of the season, so are perfectly within their rights to see that out and see what the summer might bring.
‘Or there’s an opportunity to get yourself sorted in January and have a longer-term contract and not go for the uncertainty of the summer, which will vary from individual to individual.
‘Some players take a different view, but it helps to be very, very creative in terms of the January window.’
Pompey have 13 players out of contract next summer.
However, the removal of several of the higher earners among them in January is seen as pivotal to Cowley’s recruitment.
In the meantime, the Blues would also be financially hit should escalating Covid numbers across England eventually force football to going back behind closed doors.
Cullen added: ‘At the moment, we are playing in front of spectators.
‘There could be a scenario later in January where we could be playing in front of restricted crowds or, God forbid, no crowds.
‘We have to be mindful of all those things and what we can do to remain sustainable. That will impact on what other clubs need to do as well.’
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