"He's an absolute beast of a talent!"

Hibbert tells us he doesn't think Williamson can ever be checked ... and when it comes to Z's NBA future -- Roy says there's no doubt in his mind he'll be a superstar.

Of course ... a ton of people agree -- both Carlos Boozer and Dahntay Jones told us BEFORE the hype train got rollin' that this would happen.

But, Hibbert's got no bias here -- dude went to Georgetown and has zero ties to the Dukies -- which means one thing ...