Alex Bass is braced to surrender his hard-earned Pompey first-team spot and step aside for Craig MacGillivray.
The 21-year-old was last week handed successive starts, which included a second Football League appearance.
However, with MacGillivray this week scheduled to return from Euro 2020 qualifying duty with Scotland, Bass anticipates dropping back to the bench.
The academy product has relished his first-team opportunity in the Scot's absence, once again demonstrating why those at Fratton Park hold him in such high regard.
Yet he remains realistic.
Bass said: ‘It has been a long road to get into the first team, I got the chance to play on the bench very young and, at 18 or 19, knew chances would be very hard to come by.
‘I’ve got to bide my time, I’m still very young now, and hopefully have a lot more games to play.
‘I couldn’t tell you what will happen next, I honestly couldn’t tell you.
‘Obviously, Craig has been away with Scotland and been our first choice last season and so far this, so you have to say he will come back into the team.
‘I wouldn’t know myself. I have got to keep working. I showed the gaffer what I can do on Tuesday and Saturday, hopefully I’ll get more chances in the future.
‘But you would have thought Craig will come back in, he has done well – last season he was one of our best players and done well again this season.
‘You would have thought he’ll come back, but it’s football, anything can happen.’
Bass’ previous Football League outing was on the final day of the 2017-18 campaign, appearing in a 2-0 success over Peterborough.
He was selected ahead of Luke McGee, who had made 50 appearances during what was Jackett’s first season in charge.
Following an injury-hampered loan spell at Torquay in the first half of last season, the youngster replaced McGee on Pompey’s bench.
Bass continues to serve as deputy to MacGillivray and has totalled four appearances this season spread over two international weeks.
And he has praised long-serving goalkeeping coach John Keeley for his ongoing development.
Bass added: ‘Keelo is great to me, we work very hard as a goalkeeping unit.
‘He is an experienced head and has been around the game for a long time, so knows when I’ll get my chance and knows what I can show people.
‘Keelo will keep pushing me to improve and hopefully be a future number one.’