Asked to clarify what he meant, Clayton said that Culpepper is a veteran who has lost games, so if he starts off 0-5 for the Lions, it won't be the end of the world. But for a rookie like Stafford, he has about 20-30 games before he is judged and labeled a bust. If the first five games are hopeless because the rest of the team has no chance against a tough schedule, then it could negatively affect Stafford's confidence. So throwing him into the fire too quickly as the number one pick could be a bad idea.
Remind you of anyone whose first game was against a dominant Colts team? Rodgers was able to sit for a year or two and learn the Green Bay playbook and system thoroughly, while observing and learning from a Hall of Fame quarterback. The other guy learned from an unwilling backup quarterback and a defensive-minded coach.