That will include new-boy Liam Vincent, who is deemed to be one for the future, and Reeco Hackett-Fairchild, who spent a largely uneventful loan spell at Southend last season.
But with Ronan Curtis also attracting interest and Pompey open to offers for players, that figure could easily drop as Danny Cowley overhauls the playing squad he inherited from Kenny Jackett.
With that in mind, we look at those 13 players who are currently contracted to the Blues and assess what their futures might hold.
5. Paul Downing - centre-back
Paul Downing's Pompey future has been in doubt ever since that 2-2 Fratton Park draw with Burton in September 2017. He never featured again in the league for Kenny Jackett but miraculously reappeared under Danny Cowley for the Blues' final three games of last season. The fact that he started ahead of Sean Raggett for the last game against Accrington suggests there's something there which Cowley likes. Might finally be back in favour, although unlikely to be first-choice. Photo: JPIMedia
6. Marcus Harness - right-winger/forward
Featured in all of Danny Cowley's 12 games in charge at the end of last season. Scored in the new boss' first two games in charge but failed to deliver a goal after that. Is a fantastic player to watch when in full flow - the problem is we don't see it often enough. Pompey have fielded plenty of interest in Harness in the past. No doubt that interest remains and it's fair to say a big-money bid would prove very tempting for both parties. Photo: JPIMedia
7. Michael Jacobs - Left-winger/forward
A terrific talent when fit - and that's the issue, Jacobs has had his fair share of injuries since arriving last September. Is reportedly out injured until August. That could scupper any attempt to get him off the payroll. Although, with Curtis expected to leave, Jacobs is a ready-made replacement. Photo: JPIMedia
8. Callum Johnson - right-back
A Steady Eddie - and just what Pompey need given the level of upheaval currently taking place at Fratton Park. Photo: JPIMedia