Hey, it's possible for the "Harry Potter" inspired sport to join those massive leagues -- but only if black people start playing ... at least according to Martellus Bennett.

FYI, Quidditch is a fast-paced field game that's been described as part rugby, part dodgeball ... and involves putting a ball through 3 different rings while running with a broom between your legs.

We know what you're thinking ... but Marty B gave the sport a try recently (destroying his opponents) and told TMZ Sports it's actually super fun!

In fact, Bennett says the game has real mass appeal -- "If they took it to the urban community it would be [a national sport]."

He also notes the upside is huge because "there's more Harry Potter fans than there are NFL fans."

He may have a point, the NFL is primarily an American thing. Harry Potter is a global sensation.

There's more ...

Since Bennett won a Super Bowl with the Patriots, we asked if he thought New England could be a good landing spot for Colin Kaepernick ... since Colin's attorney recently suggested the Pats had an interest.