NBA teams might not wanna plummet for Michael Porter Jr. next year ... 'cause the projected #1 pick in the 2018 Draft says there's a chance he won't jump to the pros after his freshman season.

We spoke with the 6'10", 215-pound phenom about being the big man on Mizzou's campus ... and MPJ says he's not worried about the hype surrounding him and just wants to focus on what he does on the court.