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.
9. Lincoln - 6
Out-of-contract players: Adam Jackson, Joe Walsh, Max Sanders, Charles Vernam, Jordan Wright, Sean Roughan. Photo: James Chance
10. Ipswich - 7
Out-of-contract players: Massimo Luongo, Sone Aluko, Janoi Donacien, Joel Coleman, Richard Keogh, Kane Vincent-Young, Nick Hayes. Photo: Alex Davidson
11. Shrewsbury - 8
Out-of-contract players: Luke Leahy, Tom Bloxham, Ryan Bowman, Daniel Udoh, George Nurse, Elliott Bennett, Harry Burgoyne, Charlie Caton. Photo: Pete Norton
12. Derby - 8
Out-of-contract players: Jason Knight, Conor Hourihane, David McGoldrick, James Chester, Craig Forsyth, Curtis Davies, Richard Stearman, Scott Loach. Photo: Naomi Baker