This is a tweet about using the illegal substances during pitching in the baseball game to improve the ball speed, movement, etc.
Had a good chat with @notthefakeSVP about foreign substances. We hit a lot of ground here. For those who want to understand why pitchers use them, there's that. And plenty more about what this means for the sport, why it's a big deal and what the crackdown may mean for baseball.
I know the idiom 'hit the ground' which means 'drop down to the ground'. But it doesn't seem fit to this tweet.