It would be news to me if there was a single high school, collegiate (well maybe not counting Oberlin), or professional team who did not have some sort of prayer before and/or after games. The essential gist for those of you who may not know, at least in my experience, is "thank you God for looking over our teammates and keeping us safe. Please look over x player who was injured." I certainly wouldn't consider it preaching/pushing religious beliefs upon people. If participating offends you that much? Don't bow your head. Just like you'd do in a wedding or a funeral or whatever else it may come up.
I agree with you that it *could* create problems, because this is America in 2018 and everybody has to be offended over something, but I've never heard of anyone creating a stink over it.