It would probably be an issued, but 25 or 30 years ago, hockey players didn't wear helmets and what, 50 or 60 years ago batters didn't wear helmets in baseball. Those changes eventually came, so another one would probably work out, even if not very quickly.
Originally Posted by Yachtzee
I think the problem would be getting major league pitchers to wear it. Pitchers are a very self-conscious bunch. Even if they don't think it looks silly, if it affects their delivery or takes a few mph off their fastball, they won't touch it at all.