The England Knights international, 25, goes straight into their 21-man squad for the Championship game at York City Knights tomorrow.
He has yet to play for Hull this term after suffering a knee injury in training just days before the season kicked-off.
Matongo underwent surgery in March and is now looking to salvage something from a frustrating 2021 campaign.
Hull coach Brett Hodgson said: “We’re really pleased to have Masi back from his long-term injury.
“He’s worked tirelessly over the course of the year to get himself back fit and in a position to be playing again.
“His game-time has been limited over the last year or so due to some cruel luck with injuries, so this is a good opportunity for him to play and get some much-needed minutes under his belt as he works his way back to full fitness.”
The Zimbabwe-born forward has played 59 times for Hull - but just five times since the start of last year - so offers plenty of experience to John Kear’s Bradford side who have also named scrum-half Danny Brough for the first time since he was injured in June.
“We had agreed a deal prior to deadline but, because of Covid issues at Hull, Masi wasn’t able to join until this week,” said Kear.
“He’s had a long injury similar to Matty Dawson-Jones.
“But he is clawing his way back to full match fitness and with a player of that quality, of that ilk, if we can get him here and help him recover his match fitness and bring that quality he has with his ball carries then it will do us the world of good.
“It is a deal that suits all parties; we will benefit as he will be here until the end of the season and into the play-offs.
“Every game he will get better and he will be part of the squad that travels to York.”