Drew Lock started nearly every game in four years at Missouri, throwing for 12,000 yards and 99 touchdowns. His first game as a Denver rookie, he looked like he'd never thrown a pass in his life. No excuses.
In 2016, Denver selected Paxton Lynch with the #26 pick in the NFL Draft, and he responded with four starts and four touchdowns in two years. And, he's not in Denver anymore, he's now in Seattle.
Dallas selected Dak Prescott with the 135th pick in the same draft, and in three years as Dallas' starting QB, he responded by throwing for almost 11,000 yards, 67 touchdowns, and rushing for 18 touchdowns.
Ironically, Dallas failed to make a first-round deal with any team in the 2016 NFL Draft to move up to select the quarterback they wanted ... Paxton Lynch. They had to settle on Dak Prescott.