They're saying a fastball pitch-- 340 joules or so of energy.

The thing is, you need to be going implausibly fast to have a proton have a fastball level of energy. Even at .99999999 C, a hydrogen atom still has less than a microjoule of energy. You need a lot of 9's to get up to 340 joules.

  1/sqrt(1-(0.99999999)^2) * (1 atomic mass unit * (speed of light)^2
  1.05529895 × 10-6 joules

I assumed they meant a baseball at baseball speed.

Rather than relativistic speeds, which would be bad:

https://what-if.xkcd.com/1/

I feel like regardless of the exact speed of the baseball, that's somewhat more energy than a typical proton.

A baseball at football speed, of course