Among those are the likes of Sean Raggett, Marlon Pack and Joe Rafferty as well as Joe Morrell and Colby Bishop, who have both been linked with Championship switches.
It comes after eight members of the head coach’s side were released at the end of the season following a disappointing eighth-placed finish in League One.
Names including Clark Robertson and Michael Jacobs departed, while Ronan Curtis and Jay Mingi remain in negotiations over fresh terms.
But as Mousinho readies his squad ahead of a potential promotion push, what is the current state of play regarding contracts?
We’ve taken a look at each individual who has a deal beyond this summer and their latest situation at Fratton Park.
Here’s what we found.
1. The state-of-play with every contracted Pompey player
From left: Joe Morrell, Sean Raggett, Joe Rafferty, Colby Bishop. Photo: National World
2. Josh Oluwayemi
The youngster had an option in his contract triggered at the end of the season meaning he will remain at Fratton for another 12 months. The 22-year-old could be sent out on loan in the upcoming campaign to gain regular game-time. Photo: Jason Brown
3. Joe Rafferty
The right-back remains under contract until at least 2024 after he penned a two-year deal from Preston last summer. He had an outstanding end to the campaign after injuries saw him miss five months of the season. Photo: Jason Brown
4. Zak Swanson
Swanson has been absent since January with a hamstring injury but featured 15 times in League One for the Blues. After arriving from Arsenal last summer, his current contract is set to expire in 2024 with the club holding an extra 12 months in his deal. Photo: Jason Brown