I figure, Tennis balls won't give you stitches
Yeah but they can put your eye out.
There was a story on the local news this afternoon about a tennis player here at UK who got hit in the eye, is now blind in that eye, but is one of the premier players on the team and a big reason they made the NCAA tournament this year. I tried to find a link, but they didn't seem to have it updated, sorry.
I'll try to dig it up later if I can find a link.