Tony Mowbray has confirmed that Rovers will be without Ryan Nyambe for this weekend's trip to Gillingham.
The defender, who has been a regular at right-back in 2017/18, was forced off in the early stages of last weekend's 3-0 win over Blackpool at Ewood Park.
Striker Danny Graham also had to withdraw through injury during second-half stoppage time after "popping out a rib" in a challenge.
Asked to provide an update ahead of the game against Gillingham, Mowbray said: “I generally study the opposition before making my team selection.
"I like to keep my defensive line pretty consistent, but this week Ryan Nyambe – who has played most of the season - won’t be playing because of a hamstring injury.
“He's got a grade-two hamstring [tear], so he’ll be out for four to six weeks, which is disappointing for both him and us.
"It’s part of football though and we have to move on.
"Danny Graham was positive around training and will hopefully be on the train to Gillingham with us. If not, it will be another issue which we have to resolve.
"Some are getting closer than others, Ben Gladwin was going to play [for the Under-23s] in midweek but he’s not quite ready. There’s no need to rush him, so he’ll just miss out this week."
The boss also spoke about Harry Chapman's progress, and says injuries won't stop his side going to Gillingham with a positive outlook.
“Harry should be playing for the Under-23s tonight at Villa Park. I’m pretty sure he’d have been coming to Gillingham with us if the midweek game wasn’t postponed.
"I just feel that, for his own mentality, he needs to get on the pitch and play a match first. I’d suggest that if he comes through tonight, he’ll be in the set-up for the Bradford game.
"The core of the team knows what’s expected and demanded in each game, so we’ll travel to Gillingham with a positive mentality."