The head coach has already expressed his interest in making summer swoops for Matt Macey, Owen Dale & Joe Pigott, who have starred since his arrival.
Not just that but the 36-year-old also has the task of determining who he wants to keep with 10 of his permanent senior men out of contract at the end of the season.
But as Mousinho looks to build his side for the next term, what are the chances of his current loan members remaining at Fratton Park?
We’ve taken a look at the 34 men who joined the Blues on a temporary basis since the Eisner era began in 2017 to see if any judgments can be made ahead of this summer’s talks.
Forgotten any of these names?
33. George Hirst
Despite a difficult start to the season, Hirst would end last term as the Blues’ top scorer in all competitions. Cowley was unable to land the front man for a second spell from Leicester in the summer and, after a brief spell at Blackburn, is now on loan at Ipswich. Photo: Jason Brown
34. Josh Griffiths
Had to fill the boots of Bazunu in goal for the Blues and kept eight clean sheets in 28 outings in the first half of this season. He was recalled by West Brom in January and has made seven appearances since his return. Photo: Barry Zee
35. Josh Koroma
Although the winger showed glimpses of his qualities in his opening games at Fratton Park, he struggled to impress and would return to Huddersfield in January after Pompey cut his loan stay short. He’s now scored one goal in seven outings upon his return to the John Smith's Stadium. Photo: Jason Brown