Whether it’s Mitchell Trubisky or Deshone Kizer or well, any rookie quarterback in the foreseeable future that underwhelms, the new theory for optimism is “Well look at how lost Jared Goff was as a rookie!” There is no doubt that Goff was terrible as a rookie and it’s equally true that he was excellent as a sophomore. Goff pulled off a remarkable worst-to-first campaign, ranking last in ANY/A in 2016 and then first in ANY/A in 2017. He increased his ANY/A average by 4.90, the greatest year-over-year increase in NFL history. That is why he is the exception.

I looked at all quarterbacks who (1) were 24 or younger during their rookie season, (2) threw at least 150 passes as a rookie, (3) threw at least 150 passes in their second year, and (4) entered the league in 1969 (when we first have sack data) or later. This naturally biases results in favor of second-year passers who improve, as quarterbacks who struggle as a rookie and then struggle in year two may not hit the 150-pass attempt threshold. Regardless, Goff’s improvement was truly remarkable. He finished 3.39 below league average in ANY/A in 2016 and then 1.82 above ANY/A in 2017. The graph below shows all passers who met the four criteria above. On the X-Axis, their Relative ANY/A as a rookies; on the Y-Axis, their Relative ANY/A as second-year players. A quarterback who is bad as a rookie and good as a sophomore would therefore be on the upper left quadrant of the chart, which is precisely where Goff (shaded in red) sits:

You might be able to guess the other big outlier on the chart, sitting at -0.80, 3.31. That’s Nick Foles.

And while Goff may be a promising data point for fans of Kizer or Trubisky, don’t forget that

Akili Smith, Steve Fuller, and Blaine Gabbert struggled as rookies, too — and never turned it around. There are examples on both sides — Aikman, Bradshaw, McNabb — but expecting a Goff-like improvement is absurd.

The table below shows the full set of quarterbacks shown above.