And Kenny Jackett believes the policy switch was imperative towards retaining the club’s brightest young talent.
Earlier in the season, the Blues hierarchy revealed they had shelved talks on new deals to focus squad attention on promotion.
That affected 10 players whose contracts expire at the season’s end, with Anton Walkes having now departed.
However, Bass was today handed a three-year-and-a-half year contract, tying him to Fratton Park until the summer of 2023.
His existing agreement finished in the summer of 2021, but Jackett explained Pompey’s approach made sense.
He said: ‘We have signed a couple of younger players to longer deals, Alex being one of them and Haji Mnoga the other.
‘They are the ones that are slightly different because they are more long-term thinking.
‘It wasn’t expiring soon, but I felt it was good to show confidence in him as a young goalkeeper, with it being such a difficult position.
‘We’ve had a good one in Craig (MacGillivray) in the last couple of seasons and before that Luke (McGee), so we have been okay.
‘If you haven’t got that department right it is hard to be successful.
‘Alex is young for a keeper, has a good temperament and I do feel it’s the right thing to do.
‘Similarly, I like the fact he has committed his future to us as well – and I think that gives us encouragement.’
The highly-regarded Bass had previously signed a three-year deal in July 2018.
His latest contract follows Mnoga, who penned his first professional contract just before Christmas.
The second-year scholar has signed on until the summer of 2021 as his encouraging progress continues.
Jackett added: ‘There one or two underneath, with Alex, Haji and also Reeco (Hackett-Fairchild), who played for the reserves on Tuesday at Plymouth and did very well, scoring.
‘We are always looking at that tier underneath if we can, while the main priority is obviously trying to do well this season.’