Kenny Jackett insists Pompey’s fringe players are not yet demonstrating discontent over their first-team absence.
And he has urged his shadow men to remain focused, with a chaotic period of 12 matches in 43 days looming.
The League One leaders’ outstanding start to the campaign has been constructed upon a settled starting XI.
As a consequence, members of the Blues’ sizeable squad have been restricted to support acts during the impressive progress.
Former regulars and popular presences such as Brett Pitman, Danny Rose and Christian Burgess continue to await opportunities for Jackett’s side.
Loanees Andre Green, David Wheeler and Joe Mason have all been hampered by injury, yet been on the bench when fit.
Pompey’s boss, however, wants his squad to stay patient ahead of a busy schedule.
Jackett said: ‘I don't think people are happy to be out of the team but, if you are looking from Scunthorpe, there are 12 games in 43 days.
‘We are going to need everyone, we are going to need all of them to be ready and, while some may be frustrated, my message to them is I understand.
‘Most importantly, be ready because there are going to be chances coming thick and fast.
‘That’s the reason you are here and you have to be in the right condition mentally and physically to be able to take that opportunity.
‘Some listen to that advice, some don't, but I think we have a good group, I think we have a focused group.
‘Of course you can sense the frustration in people not playing, but similarly the team has been settled, it has been successful, and not too many really have been able to knock on my door and say there is reason to change.
‘You have more trouble keeping players out of the side happy when you are losing or near the bottom of the league because obviously they have a better case to put to you.
‘When you plan a squad, you never know if injuries or suspensions may happen, you can never tell.
‘That is why you try to get two players for every position and keep as many as fit as possible.’
Pompey have used 27 players so far this season, emphasising the size of Jackett’s squad.
There also remains a wealth of talent, a strong pool Pompey’s boss believes is driving first-team regulars onto better performances.
He added: ‘The other side of it is, while it has been quite successful so far, maybe that is the reason you are so successful.
‘Our centre-halves Whatmough and Clarke are playing well at the moment. Are they playing well because Burgess is there?
‘I would suggest that’s a consideration as well when you have a successful team. Certainly people on the fringe are competing for places and keep the pressure on the players in the team.
‘You turn up for games and turn up for training and have good players or established players in your position – and I am sure it keeps you on your toes.’