Swedish international Olsson limped out of Saturday's exciting 5-3 win over Bristol City with a hamstring strain and whilst it is hoped that the injury was caught quickly, the games this week at Ewood are likely to come too soon for the wide man.
Also in danger of missing the match against the Tykes is central defender Gael Givet after he also left the field early in the first half after bursting a blood vessel.
Speaking after the match Rovers boss Steve Kean confirmed the injuries: "We lost Markus early with a hamstring strain which was a blow.
"Then Gael Givet has had to come off with a burst blood vessel at the top of his leg, so that made it difficult for us.
"But we'll patch everybody up, we've got a squad and we'll use that coming into the next two games."
Tickets for Tuesday's match at Ewood will be on sale right up until the 7.45pm kick-off. Pre-order your tickets online today at www.onerovers.co.uk
and collect them on the day of the game from the Blackburn End collection point.
Ticket prices start from £15 for Adults, £10 for Seniors and £5 for Juniors.
Supporters are also reminded that it isn't too late to purchase a 2012-13 season ticket.
Season tickets in the Ronnie Clayton Blackburn End, Darwen End and Riverside stands are still available from just £259 – which provides supporters with the equivalent of nine FREE games against matchday prices.
So to give Rovers’ promotion push a major boost, get behind the boys and buy a season ticket today!