But the Blues boss doesn’t anticipate any new transfer business being announced before the transfer window opens on June 10.
Cowley is fearful of Pompey losing out on targets, if they announce deals before the period when players can be registered begins next month.
A busy period of transfer business lies ahead this summer, with Cowley facing a lot of work to reshape his squad.
Pompey have already been lined with a stack of players in all positions, with just 14 senior men currently tied down for the new term.
Although nothing has been announced yet, Cowley is clear that plenty is happening in the background when it comes to new faces arriving.
Chief executive Andy Cullen issued a warning earlier this month, over clubs potentially hijacking deals for players under new window regulations in the EFL.
Cowley believes Cullen was right to highlight the issue.
He said: ‘What Andy (Cullen) has said is 100 per cent right.
‘Ultimately all of these clubs who are announcing players before June 10, these players aren’t actually registered with the league.
‘So really those contracts are null and void, at this moment.
‘Players who are being announced by certain clubs, those players aren’t officially their players yet. They won’t be until June 10.
‘There’s work going on behind the scenes here, though.
‘And there are things you can do to get deals into a good place. We are certainly doing that.’
Bolton, Shrewsbury and Cambridge United have been among the sides in League One to announce deals for new players so far in the closed season.
Bolton have publicised the signing of Jack Iredale, who becomes a free agent when his contract with Cambridge expires on June 31.
Meanwhile, Shrewsbury have agreed a deal with Coventry to sign Jordan Shipley on a three-year deal for an undisclosed fee.
Cambridge have agreed terms to bring in Reading’s James Holden on a two-year agreement, also for an undisclosed fee.
There hasn’t been remotely like the number of deals announced in previous closed seasons at this stage, however.
Elsewhere, the likes of Bristol City, Cardiff, West Brom and Bradford have all publicised transfer business.
And it’s the potential to lose players who may be lined which is leading to the safety-first approach.
Cowley said: ‘I don’t think we’d be announcing deals publicly yet, because the moment you announce them publicly you’re ultimately making everyone else aware.
‘We’re alerting everyone else.
‘Everyone will know what the EFL regulations are - and then they could potentially take those players.’