If a kid is held back that is between he/she and the parents. I cannot say it is the "norm" for the upstate but it happens a lot. Some for grades, some for maturity and yes I am sure some to get a little advantage on the field by being a year older than others.
I wish I had held my boy back. I have never once heard of a parent who regretted holding their child back. I have often heard parents say they wish they would have held their kid back when he was younger. Even if things don't work out for the "sports" just being a year older going to college cannot hurt.