I think I remember Roethlisberger’s very first game. IIRC Pittsburgh had both the first and second string quarterbacks injured in the same game, so they put in the 3rd string quarterback, an unknown from a small Ohio school (Miami of Ohio?).
He immediately started throwing incredible passes and was a huge surprise.
Every once in a while. Michael Irvin got held back for a year because of off field stuff. Of course one of those incidents was months before HOF voting, so that didn’t help. Of course baseball puts a lot of extra weight on the first ballot thing too. We’ll find out in 5 years.