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.
9. Denver Hume
Despite arriving on the south coast for a reported £200,000 fee in January 2022, the left-back looks to be on his way out of Pompey. The News understands there has been interest elsewhere in the defender's services. His current deal runs for another 12 months, with the club also holding another year on his contract. Photo: Graham Hunt
10. Liam Vincent
The left-back spent the second half of the campaign on loan at Worthing, where he impressed. The defender’s current deal is set to run for at least a further 12 months at Fratton Park. Photo: Jason Brown
11. Marlon Pack
Pack returned to his boyhood club last summer, where he penned a two-year deal following his exit from Cardiff. His current terms will see him remain with the Blues until 2024. Photo: Jason Brown
12. Joe Morrell
The Welsh international is believed to have Championship interest after a fantastic season for the Blues. Morrell still has 12 months along with a club option of a further year currently left on his deal and Mousinho has made it clear the midfielder will remain on the south coast next term. Photo: Jason Brown