There is no set learning curve at any position when entering the NFL, and that is especially true at the league's most valuable one -- quarterback, which is illustrated by the 15 highest-graded rookie quarterback seasons in the Pro Football Focus era.
For every immediate success who has become an unquestioned franchise quarterback such as Russell Wilson, Dak Prescott and Matt Ryan, there have been quarterbacks who have started hot before failing to take the next step, such as Robert Griffin III, Baker Mayfield and Teddy Bridgewater.
While it's obviously better to adapt quickly to the NFL game, it's how each quarterback builds on his rookie season that puts him truly among the elite at the position.
With that in mind, here are the 15 highest-graded rookie quarterback seasons since PFF started grading in 2006: