City midfielder Jamie Devitt has been ruled out for up to four months, having sustained a torn hamstring tendon injury.
The Irishman has made two appearances in claret and amber since rejoining the club, on loan from Blackpool, last month.
The 29-year-old is to undergo surgery on the injury this weekend.
Bantams boss Gary Bowyer said: "It is a massive blow for Jamie and for us as a club. It is frustrating with the innocuous way in which he sustained the injury.
"He has settled in very well and we are going to fully support him for however long he will be missing.
"We all know injuries are part and parcel of football. It is our job and his job to rediscover the form he showed before his injury, once he returns."
The City chief has also moved to update supporters on the fitness of Jake Reeves, who is progressing well.
The midfielder has been sidelined since January 2018 and Bowyer insists the right plans are in place to help aid his recovery.
Bowyer added: "Jake is out on the training pitch every day now and is working extremely hard.
"With the length of time he has been out, it would be very unfair on the lad to try and put a timeframe on when we might see him return.
"It is important to look after him and manage him well. We have a good plan in place as to how we can gradually step up his rehabilitation, in the right manner.
"He has excellent knowledge of the game and is a great lad to have around the building.
"It is a pleasure having him in the dressing room and he has been fantastic, speaking with the likes of Danny Devine and the younger midfielders - sharing advice."
Bowyer's Bantams return to action with a trip to Walsall this Saturday (kick off 3.00pm). Supporters can purchase tickets by CLICKING HERE.