Marquette King says his music career is about to take off ... tellin' TMZ Sports if he hadn't been an amazing punter -- he'd already be bigger than Chris Brown!!
The former Raiders and Broncos punter began making beats back in high school ... but says tinkering with music on long flights during his NFL career made him a master musician.
So much so ... Marquette says he feels like if he had picked music over punting a long time ago -- he'd already be a superstar in the entertainment world.