Daniel Jones, Kyler Murray and Gardner Minshew all had some success as rookie quarterbacks. You would reasonably think they should all come back and build on that success. But it’s not that easy.

While those quarterbacks will all presumably come back smarter and more experienced, defenses are also working in the offseason – perhaps studying film to get a better read on what throws a quarterback tends to prefer in key situations.

Whatever the reason, the notion that a quarterback will come back and be better in his second year simply by showing up for work on time isn’t supported by any numbers that I see.

Instead, the counter-intuitive opposite seems to be far more likely. The vast majority of quarterbacks who play pretty well as rookies tend to regress in their second seasons.

The last 10 quarterbacks, in fact, who put up top-20 per-game numbers as rookie all came back and finished with worst numbers the next year. Baker Mayfield most recently. A year ago at this time, he looked like a sure top-10 quarterback – maybe top-5 – but he sputtered through a forgettable second season.

The chart below doesn’t include four other quarterbacks who posted top-20 numbers as rookies but didn’t start at least half the time in their second season (Chris Weinke, Matt Leinart, Matthew Stafford, Nick Mullens). The chart includes only players who started at least half the time as rookie, then again started at least half the time in year No. 2.

You have to back to Byron Leftwich, drafted in 2003, to find a quarterback who was pretty good in his first year, then came back the next season and was even better.

This might be more of a coincidence than a trend. In each of the last three years, there’s been a remarkably good second-year quarterback – Carson Wentz, Patrick Mahomes, Lamar Jackson. None of those guys in their rookie season started half the time and finished with top-20 per-game numbers.

2003Byron Leftwich, Jac.132078.92.1515.817.3
2006Vince Young, Tenn.1315941.85.5418.814.7
2011Cam Newton, Car.16253441.31.8827.824.5
2012Andrew Luck, Ind.16273161.44.3122.922.1
2012Russell Wilson, Sea.16195311.63.2520.820.7
2012Robert Griffin, Wash.15213541.33.4724.221.3
2015Jameis Winston, T.B.16253131.38.3821.821.6
2015Marcus Mariota, Tenn.12235211.58.2522.221.5
2016Dak Prescott, Dall.16229181.44.3821.220.4
2018Baker Mayfield, Clev.13271102.08.0023.019.6
2018Josh Allen, Buff.1118255.91.7322.821.6
2019•Daniel Jones, NYG12251232.00.1724.2?
2019•Kyler Murray, Ariz.16233341.25.2521.9?
2019•Gardner Minshew, Jac.12237281.50.0021.0?

—Ian Allan