Josh King will miss Saturday's trip to Bournemouth due to injury.
The Rovers forward picked up a hamstring strain moments after coming on as a second half substitute during the midweek match against Norwich City.
The Norwegian international underwent a scan on Wednesday but whilst it isn't yet known how long the attacker is likely to be absent, he will miss the weekend game at the Goldsands Stadium.
"He's been for a scan and I'm afraid it is just going to be a case of monitoring that at this moment in time," revealed the Rovers boss.
"We'll have a clearer idea when it has properly settled down but it is safe to say that he won't be involved this weekend. Then we'll just have to reassess and go from there."
Introduced at half-time on Tuesday, King looked set to make an immediate impression after a strong forward run to stretch the Norwich defence, but having felt his hamstring he was quickly replaced.
Bowyer added: "It is a blow because the change that we made on Tuesday night looked like it was going to pay dividends straight away because he's got in with fantastic pass and a good run.
"So to have lost him like that was a big blow as it was an area we thought we could target in the second half.
"He's an explosive type and they are always suspect to those kind of injuries, but provides somebody else with an opportunity and it is up to them to try and take it."
Elsewhere there are just bumps and bruises to assess from their midweek exerts, but Tommy Spurr is back after illness, and David Dunn is available after recovering from a calf strain.
Tickets for Saturday's match at the Goldsands Stadium will go off sale at Ewood at 4.00pm Friday. After that tickets will be on sale at the ground of the day of the game. Cash only from the away turnstiles. Prices are £26 Adults, £14 Seniors/Students/U16s, £7 for Team Rovers members.