Detailed: Unravelling Portsmouth boss' fresh selection agony - with Liverpool, Newcastle and West Ham recruits under threat

The potential return of Freddie Potts following a calf injury would leave the Blues head coach with six available loanees and just five match-day slots.

Rob Atkinson, Kaide Gordon, Adil Aouchiche, Isaac Hayden and Mark O’Mahony are the other loan players at his disposal - yet someone must miss out against QPR.

Here are the permutations for Mousinho as he agonises over an ongoing issue during the remaining 13 matches of Pompey’s Championship season...

Rob Atkinson

Having not played competitive football for almost two years following persistent injury issues, the impressive central defender has now made eight appearances during his Pompey loan.

Encouragingly, that tally includes four successive 90-minute outings over recent weeks, demonstrating his body’s return to a physical robustness to cope with match demands.

Atkinson has shone in the left-sided centre-half role and demonstrated he will be a pivotal figure in Pompey’s ongoing battle to remain in the Championship.

Certainly it will not be an option to leave him out of the squad against QPR, particularly with Conor Shaughnessy potentially out for up to two months and Regan Poole only having returned to contention last weekend.

Ultimately, however, Atkinson’s consistently outstanding performance will dictate he simply cannot be dropped to meet loan regulations - and neither would anyone expect him to be.

Isaac Hayden

The Newcastle man has now made eight appearances for the Blues, with his display at Oxford his best yet in the shirt, as he builds up his fitness.

Before his Fratton Park arrival, the 29-year-old hadn’t featured in competitive football for eight-and-half months, ironically during a loan spell at Saturday’s opposition QPR last season.

Perhaps not unexpectedly, it has taken Hayden a while to come up to speed, although he has still to complete 90 minutes, with Oxford his longest time on pitch at 84 minutes.

Still, having been recalled to the side in place of the injured Freddie Potts, Mousinho’s men have registered successive victories over Cardiff and the U’s to put further distance between themselves and the relegation zone.

When Potts returns, Hayden again could find his place under threat, particularly considering the impressive form of Andre Dozzell, while Marlon Pack is a consideration from the bench.

Mousinho must decide whether he needs four central midfielders in his 20-man squad. If not, he could well leave out one of his loanees - Hayden or Potts - to meet the five-loan match-day criteria.

Certainly in terms of form, Dozzell and Potts have performed consistently better than Hayden so far and potentially could be the favoured partnership from QPR onwards - fitness and availability permitting.

Mark O’Mahony

A goal-scoring entrance off the bench at Oxford United provided a timely reminder of the striker’s talents following two-and-a-half months on the sidelines through injury.

It was a classy stoppage-time finish from the 20-year-old, who collected Terry Devlin’s header forward with a wonderful first touch before finishing past advancing keeper Jamie Cumming.

The Brighton youngster scored twice in his opening four Pompey appearances earlier in the season in the absence of Colby Bishop, to begin his first career spell in encouraging fashion.

Now Bishop is back as a regular starter, O’Mahony and Christian Saydee offer the only available centre-forward alternatives at present.

That will obviously change when Kusini Yengi returns from long-term injury. Yet, in the meantime, surely Mousinho cannot afford to omit the Irishman from his squad in favour of including the other loanees?

Should he do so, Bishop and Saydee will be his only centre-forward options against QPR on Saturday, with another potential selection in Callum Lang now injured.

Adil Aouchiche

John Mousinho has spoken of how he regards Aouchiche as a number 10 option - a role he will now be given a run of games in following Lang’s hamstring injury.

Even with each of his cameos off the bench - with three in total since joining from Sunderland - Lang has subsequently moved to the right flank to accommodate the Frenchman.

Certainly Aouchiche is a definite starter against QPR this weekend and not one of the loanees who will be taken out of the 20-man squad.

It will be intriguing to see how he performs in potentially a first Championship start since lining up against Pompey at the Stadium of Light at the beginning of January.

Nonetheless, there have been glimpses during his outing as a substitute against Sheffield United, Cardiff and Oxford, when he totalled 71 minutes.

Kaide Gordon

The Liverpool winger has featured for just nine minutes since arriving at Fratton Park on deadline day, remaining on the bench for the last two matches.

His addition has presented Mousinho with a right-sided attacking alternative to Matt Ritchie, offering a completely different threat through his pace and directness.

Logically, his presence is required even more following injury to Callum Lang, who has operated on the right at times this side, particularly in recent weeks to accommodate Adil Aouchiche in the number 10 role.

However, it has also been noticeable that, recently, Cohen Bramall has come off the bench to play on the left wing, prompting Josh Murphy to move across to the right flank. Thereby offering another workaround.

Should Gordon be the loan player to drop out, Mousinho could instead call upon either Thomas Waddingham or Harvey Blair to bolster his attacking threat from the bench.

Yet Blair has struggled this season and not actually played since the end of November, while Waddingham is very much a work in progress and being eased into Championship life.

Freddie Potts

It’s fair to say the West Ham loanee has been one of Pompey’s more impressive - and consistent - performers over the season to date.

Until collecting a calf injury at Sheffield United, he had featured in 27 successive games, starting 25 of them. In fact, the two he didn’t start were down to Mousinho resting him at Bristol City and West Brom.

Potts has missed the last two fixtures through that calf issue, with Pompey winning both having paired Isaac Hayden and Andre Dozzell as their central midfielders.

Nonetheless, Pompey’s head coach has recently insisted Potts still deserves to be on the team-sheet upon his return due to the levels of his display before being sidelined.

The 21-year-old was initially expected to be back from injury in 10 days, which would render him available for QPR on Saturday. However, one loanee must miss out on the 20-man squad.

Mousinho must weigh up whether he needs four central midfielders on match duty - Dozzell, Hayden, Marlon Pack and Potts. If not, it could be a choice of Hayden or Potts to either start alongside Dozzell or be omitted completely.