When I get to it, I am going to have the same problem. My Day and Night quilt top only had the small amount of red prewashed, and the all red backing has been washed several times with color catchers. I wasn't going to worry about it, but I would be interested in knowing if it where a problem before I did quilt it. I know flannel shrinks a lot, but I didn't think cotton did as much. I would just go for it.