Michael Appleton will use Adam Webster solely as a full-back this season.
But the Blues boss is convinced the 17-year-old’s future lies as a central defender.
Webster made his maiden Football League start in Saturday’s 4-2 defeat at Carlisle.
The youngster was selected at right-back – the position he has featured in for all seven of his first-team appearances to date.
Appleton, however, did employ Webster in his natural position in the heart of the defence for the pre-season friendlies against Gibraltar and Brighton.
That is also the favoured position of the West Wittering youngster, who is battling to face Oldham on Saturday after limping out of the Brunton Park fixture with a hip problem.
Regardless, Pompey’s boss sees Webster as a full-back in the short-term.
And that is where he intends to play him until he is ready to resume being a central defender for good.
Appleton said: ‘In pre-season, Adam was a little bit up and down I suppose, although I expect that from kids anyway.
‘But he is whole-hearted and at the minute his best position would be full-back.
‘I’m not sure he is ready to step in at centre half at present. He makes a lot of little errors that people don’t see but become critical.
‘The first goal in the friendly against Brighton, for instance, looked like a great goal and a great finish but ultimately it was one that could have been easily stopped.
‘This is fine. It is part of the education, it is why they are only 17 or 18 years old and I understand that.
‘But I think you don’t have to make those errors so much when you are playing as full-back.
‘You have two roles as full-back. You defend one-on-ones and you defend the far stick – anything after that is an absolute bonus.
‘With a goalkeeper, if you make a mistake it is usually a goal. Being a central defender is similar, a mistake gives the opposition either a shot at goal or a goal.
‘That is why with young defenders you have to blood them into your team little by little and that is why sometimes it’s a good idea to send them out on loan and play non-league football or whatever and get an understanding.
‘With Adam it is not so much the stuff in possession, it’s the stuff out of possession which worries me at the minute.
‘He needs to see things a little bit quicker, that is where he is getting caught out.’
Having been with Pompey since the age of 12, Webster has climbed through the ranks as a central defender.
He made his debut as a substitute against West Ham in January at the age of 17 years and 10 days.
Since then he has been utilised exclusively as a right-back in competitive first-team matches.
Webster went on to make three substitute appearances last term and has played in all four matches during the current campaign, two of which have been starts.
His progress, along with Ashley Harris, continues to be highly-promising amid more uncertain times for the club.
Appleton has no doubts, though, the second-year scholar will one day establish himself in his favoured role.
He added: ‘Without a shadow of a doubt Adam will be a centre half in the future.
‘He has all the attributes to do that role when the time is absolutely right.
‘Adam is a good size, very athletic, reasonably quick and has a reasonable pass on himself.
‘He’s a bit away at the minute but that means nothing other than it is an opportunity for us to progress him in the right way.
‘This continues to be an education for him and he will get only better from it.’