Originally Posted by
rogerstg
They are for sweat management.
+1 I had a teammate who wore one. He probably got the idea because he played high school football as well. I sometimes use one of those versatile tubes of fabric than can be made into a headband, a skull cap, ear covers, turtle neck, etc. I almost always wear something on my head because otherwise, my receding hairline and the helmet holes make for some pretty interesting suntans/sunburns.