Astros closer Roberto Osuna just caught a huge break ... with prosecutors dropping the assault charge in his domestic violence case Tuesday.
As TMZ Sports previously reported ... Osuna was suspended 75 games without pay by the MLB after he was arrested for assault in Toronto after allegedly roughing up his GF.
But when the 2017 All-Star showed up in court Tuesday, he was let off easy -- getting his charge dropped and entering into a peace bond -- a restraining order-type agreement where he's not allowed to have contact with the alleged victim for the next year.