The Jake Paul vs. Tommy Fury fight just got a helluva lot more interesting -- ex-NBA star Deron Williams (yes, the dude who played for the Jazz) has been added to the undercard ... and he could be going up against none other than former NFL running back Frank Gore!!!
Williams -- the third overall pick to the Jazz in 2005 -- reportedly just signed on to follow in Nate Robinson's footsteps and make his boxing debut on December 18 in Tampa Bay.