Pompey may consider dipping their toes in to the free agent market should things change over the coming months.
Last year, Lee Evans was signed on a deal until the end of the season, following injuries to several central midfield options. Pompey had a 22-man squad list to deal with then but following their promotion to the Championship, second-tier teams are allowed another three players.
'There is sometimes a clamour to take a player from the free agent market,’ said Mousinho to The News in his pre-match press conference on Wednesday ahead of the trip to Sheffield United at the weekend.
‘The best ones in that market are often snapped up pretty quickly, but you never know what is available.
'Some of these players have not played for a long time either, so getting them up to scratch quickly can be difficult.’
The EFL will be expecting a 25-man squad list from Championship clubs soon, and it will be interesting to see who will feature on Pompey's list. If they name less than 25 then that will allow them to sign a free agent, as long as they were released before the January transfer window shut.
As seen in January, Pompey's stance on loans changed, and they ended up signing Rob Atkinson, Isaac Hayden, Adil Aouchiche, and Kaide Gordon. They've got six loan players now, so there's a selection headache for the manager when all of his players are fit.
With Mousinho and sporting director Rich Hughes proving they are flexible when it comes to transfers, it shows that the door can’t be entirely closed on free transfers. There’s a few players with a vast amount of experience in the Championship which could help get them over the line in terms of their relegation.
Take a look below at the players who are free to be snapped up even after the winter transfer window has closed for business.

1. Jake Livermore
Captained West Brom and was once signed for £10m, though that was eight years ago. Got 247 games of Championship football under his belt and would be a good option in the centre of the park. Livermore could benefit some like Freddie Potts who is just at the start of his career. | Getty Images Photo: Getty Images

2. Jeff Hendrick
Another player with an immense amount of experience in the Championship. Played 262 times in the second tier with 27 goals and 20 assists. The 79-time Republic of Ireland international also played just under 150 times in the Premier League. Without a club since leaving Newcastle United last summer. | Getty Images Photo: Stu Forster/Getty Images

3. Jamie Paterson
Returned to England after a brief spell under Dean Smith with Charlotte in the MLS. Paterson is a versatile player across the forward line which is what John Mousinho was looking for before he landed Adil Aouchiche. The 33-year-old has a record of 55 goals and 52 assists in 34 Championship games. He's currently training with Coventry City. | Getty Images Photo: Ryan Hiscott/Getty Images

4. Brandon Williams
A free agent since being released by Manchester United. Had loan spells with both Ipswich Town and Norwich City. The 24-year-old has only 15 Championship appearances under his belt but he has played 47 times in the Premier League and also two games in the Champions League. | Getty Images Photo: Alex Pantling/Getty Images