Of course, the Blues could well plunder Premier League and Championship academies for loan gems to get their final players in before September 1.
But Danny Cowley has hinted there is a deal advanced for a young talent operating at a lower level.
So we’ve looked at some of the hottest prospects from around League Two and the National League who could be interesting Pompey and their rivals.
13. Jordan Davies
Exciting 23-year-old Welshman bagged 15 goals from the left flank in an impressive term for Wrexham. (Photo by Lewis Storey/Getty Images) Photo: Lewis Storey
14. Andrew Dallas
At home in attack or off the left flank, the Solihull Moors man's stock rose off the back of 23 goals and a further five assists in the National League last season. Photo: Nathan Stirk
15. Joe Sbarra
Has league experience at Burton but the 23-year-old midfielder impressed with 18 goals for Solihull Moors and likes to pop up in space on the left and hurt teams with his right foot. Photo: Michael Regan
16. Kabongo Tshimanga
The DR Congo man smashed in 24 goals for Chesterfield in the National League last season. (Photo by Lewis Storey/Getty Images) Photo: Lewis Storey