The 23-year-old has joined the League Two side for the remainder of the season, with Danny Cowley keen to find him regular first-team football.
Bass has made seven appearances this term, with two clean sheets, yet is behind Gavin Bazunu as Pompey’s first-team goalkeeper.
With Bass finalising his Valley Parade move over the weekend, 16-year-old Toby Steward was named on Cowley’s bench in the 1-0 loss at Sunderland.
Bass has featured 41 times for Pompey, yet appeared just twice in league football since the play-off semi-final penalty shoot-out defeat at Oxford United in July 2000.
During that time he has recovered from two broken legs, with Craig MacGillivray and then Bazunu establishing themselves as the Blues’ number one.
Speaking to Bradford’s website, he said: ‘It is a pleasure to be here. The manager has been watching me for a while and spoke about the opportunity to come to Bradford City, and it was one I was delighted to take.
‘Playing in front of vocal supporters is something I am used to from my time at Portsmouth. I am looking forward to playing football in front of a great fanbase up here, and taking on a new challenge. I cannot wait to get going.
‘I have a couple of days of training now to get to know the boys and build relationships with everyone, before getting ready to attack the game on Tuesday.’
Bass is expected to make his Bradford debut on Tuesday evening, when they make the trip to Matt Taylor’s Walsall.
Richard O’Donnell and Sam Hornby have been the goalkeepers fielded by boss Derek Adams this season, with Bass set to dislodge them to claim regular first-team football.
Bantams boss Adams told the club website: ‘Alex is a player I have watched for a number of years at Portsmouth, so I am pleased to be able to bring him to the club.
‘He came through the youth system at Portsmouth when I was manager of Plymouth Argyle. He is very highly thought of there and arrives with me having monitored his progress closely.
‘Alex has experience of playing in League One with Portsmouth this season, and carries a lot of attributes I value in a goalkeeper, so I am looking forward to seeing him perform at Bradford City.’
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