The American international keeper pulled a stomach muscle in the final few seconds of last weekends win against Manchester Utd at Ewood Park and will be forced to sit out Rovers games against Tottenham on saturday and Birmingham City on the final day of the season the week after.
Peter Encklemen, who is yet to make his first team debut since signing on a permanent deal from Aston Villa in January, is expected to deputise during Friedel's absence.