Patrick Mahomes' tape in the lead-up to the 2017 NFL draft was scary. It was littered with off-balance passes, sidearm deliveries, leaning throws, backward drifts and lots of improvisation. His footwork was frantic, he didn't consistently step through to his target and he looked more like shortstop hurling a baseball across the diamond on the move than a potential first-round franchise quarterback.
You can typically tell when a ball is going to be a completion just by watching what happens before it leaves the quarterback's hand. And so much of Mahomes' tape from his Texas Tech days featured the mechanics you'd usually see on an incompletion.