Portsmouth boss on Ryley Towler 'surpassing expectations' - and why he prefers Marlon Pack

However, he believes Marlon Pack’s ‘different profile’ presently gives Pompey’s skipper the edge in the battle for a centre-half spot.

With Conor Shaughnessy and Rob Atkinson still on the sidelines, the Blues look set to retain Pack and Regan Poole as their central defensive partnership for Sunday’s clash with league leaders Leeds.

That represents more disappointing news for Towler, who hasn’t featured since January’s 5-1 hammering at West Brom.

And while some of the Fratton faithful are calling for the left-footer’s return to the side, Mousinho has explained the thinking behind his preference for Pack in the role.

Pompey’s head coach told The News: ‘With every position, there is no set process, sometimes it’s on a bit of a feel in terms of what you feel is going to be best for the game.

‘We look at training, we look at the contribution the players have had in previous games, sometimes we just think certain matches are going to suit certain players.

‘Marlon has played plenty of football there at centre-back, we’ve had a lot of success with him there as well.

‘We looked at the games Marlon and Regan have played together. The four previous matches were Preston, Swansea, Bristol City and Norwich - and we had actually gone unbeaten in those four and won two of them. Regan then came out of the side after Norwich, so we thought that would be a good centre-half partnership at Luton.

‘Ryley has probably surpassed expectations this season in terms of his contribution to the team in the Championship. He’s been a big part of it as well, you look at some of the games Ryley has played in.

‘Particularly around Christmas time and into January, when he was a big part of the better performances against Watford, there were wins against Swansea and Coventry, a decent-enough display at Sunderland. Ryley has more than contributed this season.

‘However, Marlon just gives you a bit more experience. It’s very, very different when you’ve played that amount of games at that age and you’ve got that experienced head on your shoulders, sometimes against some of these bigger and better sides.

‘That's what Marlon gives you. He’s also a different profile in terms of centre-half on the ball. There are big differences between the two of them. We take everything into account when we’re making that selection decision.’

Sixth-choice centre-half for Pompey

Towler started the season in Pompey’s side, featuring in the opening five matches, including at Leeds in the Championship curtain-raiser which finished 3-3.

He has since totalled 12 league appearances, compared to six in the League One title-winning campaign last term.

At times he has been behind Shaughnessy, Atkinson, Hayden Matthews, Regan Poole, Pack and Tom McIntyre in the centre-half battle.

Yet he continues fighting back and at Luton returned to the bench for the first time in seven matches, albeit following yet more injuries to his rivals.

Mousinho added: ‘Ryley has to keep going, keep training hard, keep training as well as he possibly can and just be ready for the chance.

‘He’s done that really well this year. He started the season, he came out of the side, he kept himself going, then he got back into the team. Now he has to do that again.’