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.
5. Jordan Maguire-Drew
Delivered a regular return of goals and assists as Grimsby returned to the EFL last season, the former Brighton youngster already has plenty of league experience in the bank. Photo: Justin Setterfield
6. Ryan Barnett
The 22-year-old right winger was an important part of the Solihull Moors team which reached the National League play-offs last season season, producing 11 assists and six goals for his side. Photo: Getty Images
7. Brandon Thomas-Asante
A name which has been mentioned in the same breath as Pompey's on more than one occasion. The rapid attacker married 13 goals with five assists in an excellent League Two campaign for Salford. Photo: Lewis Storey
8. Harry McKirdy
Danny Cowley wants pace, goals, assists and someone who can play up front or off the flank. McKirdy ticks all those boxes after bagging 22 goals and seven assists for Swindon last term in League Two. Photo: Ben Hoskins