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Data Entry: Searching for Stats to Contextualize Trubisky’s Rookie Season

| January 30th, 2018

I recently looked at Trubisky’s rookie performance in “quarters” – four-game sets – and found that he showed continual growth in both usage and efficiency (in all areas but throwing touchdowns) as the season progressed.

Now I want to look at how that growth compares to other recent quarterbacks in their rookie seasons. Do quarterbacks who are going to be good show more growth during their rookie season? Do those who stay the same, or get worse, tend to bust?

The Set-Up

I looked at all QBs drafted in the 1st round who played at least twelve games of their rookie season within the last 10 years and tracked their progress in four-game samples. All data was compiled using the Pro Football Reference game play finder. Allow me a brief explanation of my 3 limits:

  • 1st Round Picks. I wanted players similar to Trubisky, who were drafted with the expectation of playing early. Later round picks often have to earn the job so I didn’t want to include them and skew the data.
  • In the Last 10 years. The NFL passing game continues to evolve, as does the college passing game that prepares them for the NFL. Comparing rookie QBs now to rookie QBs from 20 years ago just isn’t reasonable. Heck, even comparing now to 10 years ago isn’t great, but cutting it much shorter than that really limits the sample size, which is already pretty small.
  • Who Played Twelve Games as Rookies. I’m tracking growth in four-game samples, and two sets of data isn’t really enough, so twelve games gives some sort of growth trend through at least 3 sets.

These stipulations gave me a sample size of 16 quarterbacks: Matt Ryan, Joe Flacco, Mark Sanchez, Sam Bradford, Cam Newton, Blaine Gabbert, Robert Griffin III, Ryan Tannehill, Brandon Weeden, Andrew Luck, Teddy Bridgewater, Blake Bortles, Jameis Winston, Marcus Mariota, Carson Wentz, and Mitch Trubisky.

Before doing this study, it seemed fairly logical to me that most rookie QBs would naturally improve as the season wore on. After all, they’re brand new at this and facing a steep growth curve. And you usually get better at your job within the first few months, right?

Also, take into consideration that most of these quarterbacks were starters from day one of training camp, let alone the regular season. Trubisky faced the unique scenario of not seeing first-team reps until after the first quarter, as the Bears prepared to face what was then the league’s best defense.

Nevertheless, we look at the numbers.

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