When Dak Prescott finished the 2016 preseason with a 137.8 passer rating, many observers talked about the "vanilla defenses" Prescott and the Cowboys faced.
"It’s only preseason," they said. "He won't look unstoppable against NFL defenses. He can't read NFL defenses yet."
But then he did.
That 'it's only preseason' argument is easily the most frequently used argument to discount preseason performances, be they good or bad. Dak Prescott is a case in point for how a good preseason performance can be argued away, and the QB apologists in Philly are a good example of how a bad preseason performance can also be argued away.