Bush-league
At the top of professional baseball in the US are the Major Leagues, followed by their Minor League affiliates, today broken down into AAA, AA and A classes. In the olden days, around the turn of the last century, Major League clubs utilized amateur teams to develop their young prospects.
Those ragtag teams were usually outside the major cities in areas that were more “bush”—a bit of slang from those times that meant “rural” or “provincial.” While it wasn’t intended as a slight back then, if somebody calls you bush-league nowadays, they’re basically calling you an amateur or a hack.
Alex Rodriguez, pictured here, committed an infamous bush-league play during the 2004 American League Championship Series by slapping the baseball out of his opponent’s glove.