The Norwegian limped out of the FA Cup tie after just 8 minutes with a reoccurrence of the hamstring injury that had forced him to miss the previous three matches, much to the dismay of manager Michael Appleton.
"It is his hamstring again, it is the same problem," admitted the Rovers boss.
"He's done a million and one tests in terms of his strength and we thought he was right.
"He felt right, he felt great and wanted to play so it is a shame because we are going to miss his pace in his side so that is something we'll have to look at."
Rovers are back in action this Saturday when Bristol City are the visitors to Ewood Park. Tickets for the game are on open sale priced from £15 for Adults, £10 for Seniors and £5 Juniors. Book online today at www.onerovers.co.uk