IMHO , a softly thrown ball to the grill is not a realistic risk of catastrophic facial injury like a line drive is.
I know this was said way up thread, but I wanted to comment as a cautionary tale about looking at things this way...
As a kid's parent that took a ball to the head in a warmup and suffered 9 months out of ball due to post concussion syndrome, half days of school for several months, migraines, and now anxiety issues, I will say that catastrophic facial injuries are just one part of the issue, and it's naive to only think that way. Thrown balls can do bad things.
The injury was a freak thing after the coach asked the girls to hold the balls and look at her. Mine did, her throwing partner didn't hear. Lots of late night ER visits, neurologists consults, and therapists later, I have a much stronger opinion on these things. Our kid's a catcher, and we're now trying to get all the coaches to stop telling her to throw her mask all the time when there are possible plays at the plate, too.