A resurfaced video shows a 13-year-old Flagg running basketball drills while wearing a Mavericks t-shirt. Despite barely being a teenager, Flagg is shown running back and forth across the baseline to defend a corner three-point shot. As he travels back toward the basketball, Flagg is passed the ball, which he dunks repeatedly.

NEWYou can now listen to Fox News articles! The Dallas Mavericks won the Cooper Flagg sweepstakes earlier this week when they secured the first overall selection of this year's NBA Draft. The Mavs have already insinuated the pick is not available in a trade,