Among those numbers are influential first-team regulars Marcus Harness, Louis Thompson and Michael Jacobs as well as Player of the Season Sean Raggett.
Danny Cowley revealed the Blues are yet to finalise talks with any of his out-of-contract contingent over new deals – opening up the possibility of them leaving for free come June.
But how does the Fratton Park outfit’s numbers of potential free agents compare to those across the rest of League One?
We’ve taken a look at the sides with the most players out-of-contract in the summer and who could have the biggest rebuilding job ahead.
Here’s what we found.
21. Sheffield Wednesday - 12
Out-of-contract players: Barry Bannan, Callum Paterson, Dennis Adeniran, Jack Hunt, Dominic Iorfa, Josh Windass, Marvin Johnson, George Byers, Liam Palmer, Jaden Brown, Fisayo Dele-Bashiru, Lee Gregory. Photo: Gareth Copley
22. Accrington - 12
Out-of-contract players: Ethan Hamilton, Toby Savin, Liam Coyle, Sean McConville, Mitchell Clark, Joe Pritchard, Harvey Rodgers, Michael Nottingham, Joe Hardy, Seamus Conneely, Jack Nolan, Enock Lusiama. Photo: David Rogers
23. Burton - 12
Out-of-contract players: Sam Winnall, Ben Garratt, Cameron Borthwick-Jackson, Jonny Smith, Adedeji Oshilaja, Conor Shaughnessy, Terry Taylor, Michael Mancienne, Louis Moult, Mustapha Carayol, Chris McCann, Tom Hewlett. Photo: Nathan Stirk
24. Cambridge - 13
Out-of-contract players: Ryan Bennett, Sam Smith, George Williams, Harvey Knibbs, Paul Digby, Dimitar Mitov, Shilow Tracey, Lloyd Jones, Liam O’Neil, Ben Worman, Lewis Simper, Fejiri Okenabirhie, Louis Chadwick. Photo: Pete Norton