If the batter swings and is hit by a pitch its a dead ball and its a strike.
If the pitch was in the strike zone then it would also be a dead ball and a strike.
Otherwise If the ball hits the batter first it is a hit by pitch, if it hits the bat first its a strike.
Lastly, If the batter hits the ball with one or two feet outside of the batters box he is out.
I'm convinced this wouldn't happen. At this speed, only direct collisions of nuclei would do anything. The ball would pass through the air and bat as if they weren't there... and I don't believe it would deposit an appreciable amount of energy at any particular place...<p>If you think I'm wrong, just think about how far high energy protons (cosmic rays) travel through our atmosphere before they lose their energy. Each atom of the baseball has a good probability of flying through the air for a substantial distance before interacting with anything at all.
A number of years ago I read an idea (I think it might have been in James S.A. Corey's Babylon's Ashes) that I find very compelling; any object becomes a weapon given sufficiently high velocity.
Randall's book "What If?," which is a collection of these absurd hypotheticals, is for sale on Amazon for $3 right now. I've got it, it's a fun read.<p>Edit: I should add that it's the eBook.