The Blues who today take on the Hawks at Westleigh Park in their latest pre-season fixture, begin their stay at the Football Association-owned facility on Monday.
There, they’ll be put through their paces before facing Premier League Crystal Palace in a behind-closed-doors friendly on Friday.
To date, Cowley has signed five players this summer – Gavin Bazunu (loan), Clark Robertson, Liam Vincent, Shaun Williams and Ryan Tunnicliffe.
Their arrivals have taken Pompey’s squad number up to 17 following an overhaul, leaving plenty of room for more new additions between now and the end of the transfer window.
Cowley is currently using triallists to supplement his squad, with the head coach wanting 23 players present for the trip to St George’s Park.
Injuries to Ellis Harrison, Michael Jacobs and Vincent means it’s likely that up to eight triallists will accompany the squad to their training base next week.
But that number could be reduced if Cowley gets his wish of adding to his options.
He told The News: ‘We have three not yet quite ready to train fully with us. Ellis is nearly there, so I’m hoping for him that he’ll be there by the beginning of next week.
'So that will be 15 (for St George's Park), so the remainder will be triallists.
‘Maybe we’ll sign one or two (players) before then, though.
‘We are working hard to and have everything crossed and would like to.
‘The quicker we can have these players in the building the better, that’s for sure, but we’re in a chain.’
Cowley admitted his Pompey rebuild was never going to be plain sailing.
He confessed his revamp could take him right up to the end of the transfer window – despite the season kicking off on August 7.
And he stressed that it could take another two transfer windows to get the Blues to where he wants them to be.
‘We knew this wasn’t going to be straightforward and that there was going to be a lot of hard work involved,’ said Cowley.
‘Will we be exactly where we want on August 7, probably not. August 31, I think, we will be in a much better position.
‘We know what we want to do, but you can’t do all that in one window.
‘For all the will in the world it takes 2-3 windows normally, two summer windows I always think to get the team to where we want it to be.’