Kenny Jackett foresees a Pompey future employing a back three on a regular basis.
The Blues boss admits he is open to retaining the 3-5-2 formation rolled out against Gillingham last weekend.
Recalling fit-again Jack Whatmough to partner Christian Burgess and Matt Clarke in defence, the system switch produced a hugely-encouraging first half.
However, Pompey surrendered a 1-0 lead at the interval to slump to a 3-1 defeat, marking a third-straight loss at Fratton Park.
Jackett, though, is adamant there were enough positive signs to convince the formation should not be a one-off.
He said: ‘At the right time, playing three at the back is something, if possible, I would like to be able to do.
It is something which is an option if I’ve got the players. Where and when that will be the case, we shall seeKenny Jackett
‘With everybody fit and available, it could open up three at the back, which is something I feel can be successful in this division.
‘If you look at Bristol City and Sheffield United, there are some sides which have played it very effectively.
‘You need all your components for any system to work – particularly for that one. And we have a lot of the components.
‘You need three good central defenders, while if we can get to three midfielders we can outnumber the opposition, and there is also a front two.
‘In addition, it’s very important to have athletic wing-backs.
‘There are different interpretations. There are a lot of very successful teams who play that way, while others in this division, such as Gillingham, play a number of systems, even in one game.
‘Gillingham sometimes will play three systems in one match. Bristol Rovers do it as well.
‘There are a lot of examples of people who stay flexible with three at the back.
‘It is something which is an option if I’ve got the players. Where and when that will be the case, we shall see.
‘But it is something I have mentioned (before) during the course of the season.’
On Saturday, Pompey travel to an Oldham side currently placed 19th in League One.
The re-emergence of Whatmough offers Jackett the option to again operate with a back three, despite Nathan Thompson’s being suspended and Oli Hawkins injured. Brett Pitman is expected to be available for the Boundary Park trip following his hamstring problem, handing the Blues a massive boost.
In the 3-5-2 set-up, Pompey’s skipper and leading scorer could serve as part of a front pair alongside either Kal Naismith or Jamal Lowe.
Jackett must also choose between Sylvain Deslandes and Brandon Haunstrup at left wing-back.
Although the Blues boss believes personnel rather than systems will always reign.
He warned: ‘There is a little bit of a hang-up on systems.
‘It is about balance of players. Players complementing players is more important than what system you play.
‘You can try to fit the wrong ones into the right system – and it won’t work.’