Kenny Jackett insists he knows his best Pompey XI.
But variables, such as injury and form, have so far hindered the opportunity to unleash that first-team preference.
The Blues have taken five points from their opening five League One matches during a stuttering start.
With Jackett's men once again without a league fixture this weekend, they will soon stand three games behind the majority of their rivals.
To add to the campaign's fitful beginning, selection issues have prompted several players to occupy unfamiliar roles.
Injuries to summer signings James Bolton, Ryan Williams and, to an extent, Sean Raggett have frustratingly affected Jackett’s line-up.
And that has impacted upon the Pompey’s manager’s first-team vision.
Jackett said: ‘In an ideal world, you know from day one of pre-season what your best team is, but it doesn’t work that way.
‘There’s form, suspensions, injury – and you don’t necessarily want to rotate just for the sake of it.
‘You know your best team with all players in top form and all players fit. That would be great.
‘When that doesn’t happen, then you have to come up with other things.
‘When everyone's fit, everyone’s in top form, everyone has had a consistent amount of games, that’s what you want. It’s marrying those together.
‘Teams evolve in a season and hopefully you then see more cohesion, that’s the idea. Injuries can disrupt, but you have a squad for that reason to try to overcome that.
‘Fielding your best team is where you want to get to, but sometimes it can take you a little while to get there.
‘If you can settle your team down and get a winning side and a competitive side, where both performances and results justify, then you get into a rhythm.’
For last season’s League One opener against Luton, the Blues fielded Anton Walkes in a central-midfield role, with Brandon Haunstrup on the left wing and Ronan Curtis up front.
They featured in a 4-4-2 formation, which secured a somewhat fortuitous 1-0 victory over Luton.
That side soon evolved, in both personnel and system, finishing the campaign with 88 points, fourth place and the Checkatrade Trophy.
Jackett added: ‘That first game was a 4-4-2 against Luton, with Curtis up front partnering Oli Hawkins.
‘Somewhere during that match we left Hawkins as a one and pulled Curtis out to the left, where he looked more natural. We then shuffled around.
‘There are new combinations this season, different people coming in, which always happens.
‘I do feel, generally, that performances have been better than results. Similarly, you also have to turn performance into results.’