Football is an unforgiving game. It doesn't take much to go from franchise quarterback to backup. There are always superstars who are going to keep their jobs for years regardless of what happens, but think about passers such as Carson Wentz and Matt Schaub, who went from unquestioned starters to pariahs in a matter of months. The time when quarterbacks would get years to prove themselves is long over.
Let's sort through the quarterbacks whose situations are most vulnerable after the first three weeks of the NFL season.