27-year-old David Pyant was arrested and charged with aggravated harassment back in May after sending an email to Silver, saying "If you don't let me play, I'm going to come up there and kill you with my f*cking gun."

But, Pyant won't be serving any time for the threat, 'cause TMZ Sports has learned Silver simply did not want to move forward with the case ... and the charges were dropped.

It's a HUGE break for the guy ... he was facing up to a year in jail.